Checks on `ro-crate-metadata.json` entity fail if there is a `@base` defined in the `@context`

[elichad]

Process Run Crate profile crate defines a @base URI as part of its @context:

"@context": [
    "https://w3id.org/ro/crate/1.2-DRAFT/context",
    { "@base": "https://www.researchobject.org/workflow-run-crate/profiles/0.5/process_run_crate/"}
  ],

When the validator is run on the profile crate, all the checks targeting ro-crate-metadata.json produce errors. Presumably this is because the id is changed by adding the @base and so selecting just <ro-crate-metadata.json> doesn't find the entity any more.

                                                                                            [profile: RO-Crate Metadata Specification 1.1]
     [ ro-crate-1.1_5 ]: RO-Crate Metadata File Descriptor REQUIRED properties                                                            
                                                                                                                                          
      RO-Crate Metadata Descriptor MUST be defined according with the requirements details defined in RO-Crate Metadata File              
      Descriptor                                                                                                                          
                                                                                                                                          
          Failed checks                                                                                                                   
                                                                                                                                          
       [ ro-crate-1.1_5.1 ] Metadata File Descriptor entity type:                                                                         
                             Check if the RO-Crate Metadata File Descriptor has @type CreativeWork, as per schema.org                     
         Detected issues                                                                                                                  
         - [Violation on <./ro-crate-metadata.json>]: The RO-Crate metadata file MUST be a CreativeWork, as per schema.org                
       [ ro-crate-1.1_5.2 ] Metadata File Descriptor entity: `about` property:                                                            
                             Check if the RO-Crate Metadata File Descriptor has an about property referencing the Root Data Entity        
         Detected issues                                                                                                                  
         - [Violation on <./ro-crate-metadata.json>]: The RO-Crate metadata file descriptor MUST have an `about` property                 
         referencing the Root Data Entity                                                                                                 
       [ ro-crate-1.1_5.3 ] Metadata File Descriptor entity: `conformsTo` property:                                                       
                             Check if the RO-Crate Metadata File Descriptor has a conformsTo property which points to the RO-Crate        
                             specification version                                                                                        
         Detected issues                                                                                                                  
         - [Violation on <./ro-crate-metadata.json>]: The RO-Crate metadata file descriptor MUST have a `conformsTo` property             
         with the RO-Crate specification version                                                                                          
                                                                                                                                          
                                                                                                                                          
                                                                                                                                          
                                                                                            [profile: RO-Crate Metadata Specification 1.1]
     [ ro-crate-1.1_6 ]: RO-Crate Metadata File Descriptor entity existence                                                               
                                                                                                                                          
      The RO-Crate JSON-LD MUST contain a Metadata File Descriptor entity named ro-crate-metadata.json and typed as                       
      schema:CreativeWork                                                                                                                 
                                                                                                                                          
          Failed checks                                                                                                                   
                                                                                                                                          
       [ ro-crate-1.1_6.1 ] RO-Crate Metadata File Descriptor entity existence:                                                           
                             Check if the RO-Crate Metadata File Descriptor entity exists, i.e., if there exists an entity with @id       
                             ro-crate-metadata.json and type schema:CreativeWork                                                          
         Detected issues                                                                                                                  
         - [Violation on <./ro-crate-metadata.json>]: The root of the document MUST have an entity with @id                               
         `ro-crate-metadata.json`