Revert "Test with phpbb master"

This reverts commit 3d56a42.

Author: iMattPro

.github/workflows/tests.yml

@@ -17,7 +17,7 @@ on:
 jobs:
     call-tests:
         name: Extension tests
-        uses: phpbb-extensions/test-framework/.github/workflows/tests.yml@master
+        uses: phpbb-extensions/test-framework/.github/workflows/tests.yml@3.3.x
         with:
             EXTNAME: phpbb/mediaembed # Your extension vendor/package name
             CODECOV: 1                # Run code coverage via codecov? 1 or 0