Try relative path for config file

Author: phrdang

.github/workflows/java-checkstyle.yml

@@ -27,5 +27,5 @@ jobs:
         # report on anything that is in an added/modified file
         filter_mode: file
         # fail_on_error: true
-        checkstyle_config: google_checks_mod.xml
+        checkstyle_config: ../google_checks_mod.xml
         # workdir: ./src/com/code4tomorrow  # working dir relative to root dir