Merge pull request PHPCSStandards#463 from PHPCSStandards/feature/gha…

…ctions-xmllint-bypass-apt-get-update

GH Actions: work around intermittent apt-get errors

.github/workflows/validate.yml

@@ -28,10 +28,15 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
 
+      # Updating the lists can fail intermittently, typically after Microsoft has released a new package.
+      # This should not be blocking for this job, so ignore any errors from this step.
+      # Ref: https://github.com/dotnet/core/issues/4167
+      - name: Update the available packages list
+        continue-on-error: true
+        run: sudo apt-get update
+
       - name: Install xmllint
-        run: |
-          sudo apt-get update
-          sudo apt-get install --no-install-recommends -y libxml2-utils
+        run: sudo apt-get install --no-install-recommends -y libxml2-utils
 
       - name: Retrieve XML Schema
         run: curl -O https://www.w3.org/2012/04/XMLSchema.xsd