Replace use of attr with attrs in AppController subclasses

Fixes regression from fb58b01. The problem manifested as an error with the
`app` property in an AppController subclass, and this wasn't noticed until
now due to the `app` property not being accessed in a controller that had
this problem, namely ManifestController.

Author: dsotirho-ucsc

src/azul/health.py

@@ -15,7 +15,7 @@
     Optional,
 )
 
-import attr
+import attrs
 from botocore.exceptions import (
     ClientError,
 )
@@ -83,7 +83,7 @@ def description(self):
         return self.fget.__doc__
 
 
-@attr.s(frozen=True, kw_only=True, auto_attribs=True)
+@attrs.frozen(kw_only=True, slots=False)
 class HealthController(AppController):
     lambda_name: str
 
@@ -158,7 +158,7 @@ def _make_response(self, body: JSON) -> Response:
         return Response(body=json.dumps(body), status_code=status)
 
 
-@attr.s(frozen=True, kw_only=True, auto_attribs=True)
+@attrs.frozen(kw_only=True, slots=False)
 class Health:
     """
     Encapsulates information about the health status of an Azul deployment. All

src/azul/service/__init__.py

@@ -10,7 +10,7 @@
     TypedDict,
 )
 
-import attr
+import attrs
 from chalice import (
     ForbiddenError,
 )
@@ -59,7 +59,7 @@
 FiltersJSON = Mapping[str, FilterOperator]
 
 
-@attr.s(auto_attribs=True, kw_only=True, frozen=True)
+@attrs.frozen(kw_only=True)
 class Filters:
     explicit: FiltersJSON
     source_ids: set[str]
@@ -82,7 +82,7 @@ def to_json(self) -> JSON:
         }
 
     def update(self, filters: FiltersJSON) -> 'Filters':
-        return attr.evolve(self, explicit={**self.explicit, **filters})
+        return attrs.evolve(self, explicit={**self.explicit, **filters})
 
     def reify(self,
               plugin: MetadataPlugin,
@@ -177,7 +177,7 @@ def __call__(self,
                  ) -> mutable_furl: ...
 
 
-@attr.s(auto_attribs=True, frozen=True, kw_only=True)
+@attrs.frozen(kw_only=True)
 class ServiceAppController(AppController):
     file_url_func: FileUrlFunc
 

src/azul/service/catalog_controller.py

@@ -1,4 +1,4 @@
-import attr
+import attrs
 
 from azul import (
     CatalogName,
@@ -53,7 +53,7 @@ def list_catalogs(self) -> schema.object(
                     'atlas': catalog.atlas,
                     'plugins': {
                         plugin_type: {
-                            **attr.asdict(plugin),
+                            **attrs.asdict(plugin),
                             **self._plugin_config(plugin_type, catalog.name)
                         }
                         for plugin_type, plugin in catalog.plugins.items()

src/azul/service/manifest_controller.py

@@ -8,7 +8,7 @@
     get_type_hints,
 )
 
-import attr
+import attrs
 from chalice import (
     BadRequestError,
     ChaliceViewError,
@@ -76,7 +76,7 @@ class ManifestGenerationState(TypedDict, total=False):
 assert manifest_state_key in get_type_hints(ManifestGenerationState)
 
 
-@attr.s(frozen=True, auto_attribs=True, kw_only=True)
+@attrs.frozen(kw_only=True)
 class ManifestController(SourceController):
     manifest_url_func: ManifestUrlFunc