Use variable for workspace directory

Author: ref-humbold

.github/workflows/build-and-test.yml

@@ -19,10 +19,10 @@ jobs:
       - uses: gradle/actions/setup-gradle@v4
 
       - name: Build
-        run: ./gradlew jar
+        run: $GITHUB_WORKSPACE/gradlew jar
 
       - name: Test
-        run: ./gradlew test
+        run: $GITHUB_WORKSPACE/gradlew test
 
   ant-build-and-test:
     runs-on: ubuntu-latest
@@ -36,7 +36,7 @@ jobs:
           distribution: temurin
 
       - name: Install JUnit5 for ANT
-        run: ./ci/install_ant_junit5.sh
+        run: $GITHUB_WORKSPACE/ci/install_ant_junit5.sh
 
       - name: Download Dependencies
         run: ant resolve