Update PHP version matrix to remove 8.0

Author: sifex

.github/workflows/main.yml

@@ -7,7 +7,7 @@ jobs:
         runs-on: 'ubuntu-latest'
         strategy:
             matrix:
-                php-versions: [ '8.0', '8.1', '8.2', '8.3', '8.4' ]
+                php-versions: [ '8.1', '8.2', '8.3', '8.4' ]
 
         steps:
             -   uses: actions/checkout@v2