GH Actions: downgrade actions/[upload|download]-artifact back from 4 to 3

I'm getting sick and tired of having to restart builds due to artifacts not downloading correctly.

This bug has been reported to the action runner and upgrading to v4 should not be re-attempted until the issue has been resolved.

Effectively reverts Dependabot PR 172 (and 173).

Ref: actions/download-artifact 249

Author: jrfnl

.github/workflows/test.yml

@@ -38,15 +38,15 @@ jobs:
         run: php scripts/build-phar.php
 
       - name: Upload the PHPCS phar
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v3
         with:
           name: phpcs-phar
           path: ./phpcs.phar
           if-no-files-found: error
           retention-days: 28
 
       - name: Upload the PHPCBF phar
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v3
         with:
           name: phpcbf-phar
           path: ./phpcbf.phar
@@ -163,7 +163,7 @@ jobs:
 
       - name: Download the PHPCS phar
         if: ${{ matrix.custom_ini == false }}
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v3
         with:
           name: phpcs-phar