Use workflow in PR branch.

Author: desrosj

.github/workflows/phpunit-tests.yml

@@ -36,7 +36,7 @@ jobs:
   #
   test-with-mysql:
     name: PHP ${{ matrix.php }}
-    uses: WordPress/wordpress-develop/.github/workflows/reusable-phpunit-tests-v3.yml@trunk
+    uses: ./.github/workflows/reusable-phpunit-tests-v3.yml
     permissions:
       contents: read
     secrets: inherit
@@ -115,7 +115,7 @@ jobs:
   #
   test-with-mariadb:
     name: PHP ${{ matrix.php }}
-    uses: WordPress/wordpress-develop/.github/workflows/reusable-phpunit-tests-v3.yml@trunk
+    uses: ./.github/workflows/reusable-phpunit-tests-v3.yml
     permissions:
       contents: read
     secrets: inherit
@@ -159,7 +159,7 @@ jobs:
   #
   specific-test-groups:
     name: ${{ matrix.phpunit-test-groups }}
-    uses: WordPress/wordpress-develop/.github/workflows/reusable-phpunit-tests-v3.yml@trunk
+    uses: ./.github/workflows/reusable-phpunit-tests-v3.yml
     permissions:
       contents: read
     secrets: inherit