GH Actions/CI: run the test suite against PHP 8.1, 8.2 and 8.3 (#363)

* Fix PHP 8.1 compatibility

The tests were failing on PHP 8.1 due to a `file_exists(): Passing null to parameter #1 ($filename) of type string is deprecated` notice coming from the `JobsRepository::dumpJsonFile()` method.

While it would probably be unlikely for this error condition ever to be hit in a real life situation, it is something which is likely to happen in the tests and well, a little defensive coding goes a long way.

With this fix in place, the tests now pass on PHP 8.1 and PHP 8.2 and compatibility with both can be declared. 🎉

* GH Actions/CI: run the test suite against PHP 8.1, 8.2 and 8.3

PR 361 should fix the remaining (known) PHP 8.1 error.

Once that PR has been merged, the CI runs against PHP 8.1, 8.2 and 8.3 should pass.

To that end, I'm adding builds against PHP 8.1, 8.2 and 8.3.

I'm also moving the code coverage recording from PHP 7.4 to PHP 8.2 to ensure high/low PHP is measured and adding an extra variant with `Xdebug` on high PHP too.

As PHP 8.3 is still in flux, builds against it are still allowed to fail.

---------

Co-authored-by: jrfnl <jrfnl@users.noreply.github.com>

.github/workflows/ci.yml

@@ -36,13 +36,29 @@ jobs:
                         os: ubuntu-latest
                     -   php: '7.4'
                         os: ubuntu-latest
-                    -   php: '7.4'
-                        os: windows-latest
-                        coverage: 'pcov'
                     -   php: '8.0'
                         os: ubuntu-latest
                         symfony: '^6.0'
+                    -   php: '8.1'
+                        os: ubuntu-latest
+                        symfony: '^6.0'
+                    -   php: '8.2'
+                        os: ubuntu-latest
+                        symfony: '^6.0'
                         coverage: 'pcov'
+                    -   php: '8.2'
+                        os: ubuntu-latest
+                        symfony: '^6.0'
+                        coverage: 'xdebug'
+                    -   php: '8.2'
+                        os: windows-latest
+                        symfony: '^6.0'
+                        coverage: 'pcov'
+                    -   php: '8.3'
+                        os: ubuntu-latest
+                        symfony: '^6.0'
+
+        continue-on-error: ${{ matrix.php == '8.3' }}
 
         steps:
             -   name: Checkout source
@@ -79,11 +95,11 @@ jobs:
                 run: composer config extra.symfony.require ${{ matrix.symfony }}
 
             -   name: Update composer dependencies
-                if: matrix.php != '8.2'
+                if: matrix.php != '8.3'
                 run: composer update -o --no-interaction --no-progress ${{ matrix.composer-flags }}
 
             -   name: "Update composer dependencies (PHP 8.2, ignore platform)"
-                if: matrix.php == '8.2'
+                if: matrix.php == '8.3'
                 run: composer update -o --no-interaction --no-progress ${{ matrix.composer-flags }} --ignore-platform-req=php+
 
             -   name: Run test suite
@@ -164,6 +180,9 @@ jobs:
                     -   php: '5.5'
                     -   php: '7.2'
                     -   php: '8.0'
+                    -   php: '8.3'
+
+        continue-on-error: ${{ matrix.php == '8.3' }}
 
         steps:
             -   name: Checkout