CI: pyproject-metadata 0.9.0 has been released, no need to test rc

Author: dnicolodi

.github/workflows/tests.yml

@@ -105,10 +105,6 @@ jobs:
           - os: ubuntu-latest
             python: '3.12'
             pyproject_metadata: '==0.8.0'
-          # Tets with pyproject-metadata release candidate
-          - os: ubuntu-latest
-            python: '3.12'
-            pyproject_metadata: '==0.9.0rc1'
 
     steps:
       - name: Checkout