Attempt to provide allow failure for PHP8.1 unit tests (#1847)

* Attempt to provide allow failure for PHP8.1 unit tests
  PHP8.1 Tests show as passed despite the errors, and it requires checking the actual output from the run to see what the rea result is; but I can live with that until github provides functionality for a proper allow_failure option

.github/workflows/main.yml

@@ -5,12 +5,17 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
+        experimental:
+          - false
         php-version:
           - '7.2'
           - '7.3'
           - '7.4'
           - '8.0'
-          - '8.1'
+
+        include:
+          - php-version: '8.1'
+            experimental: true
 
     name: PHP ${{ matrix.php-version }}
 
@@ -52,8 +57,10 @@ jobs:
       - name: Setup problem matchers for PHPUnit
         run: echo "::add-matcher::${{ runner.tool_cache }}/phpunit.json"
 
-      - name: Test with PHPUnit
+      - name: "Run PHPUnit tests (Experimental: ${{ matrix.experimental }})"
-        run: ./vendor/bin/phpunit
+        env:
+          FAILURE_ACTION: "${{ matrix.experimental == true }}"
+        run: vendor/bin/phpunit --verbose || $FAILURE_ACTION
 
   php-cs-fixer:
     runs-on: ubuntu-latest