fix: gradlew 실행 권한 부여

.github/workflows/gradle.yml

@@ -51,7 +51,10 @@ jobs:
         with:
           java-version: '11'
           distribution: 'temurin'
-
+
+      - name: Grant execute permission for gradlew
+        run: chmod +x gradlew
+
       ## Gradle test
       - name: Run tests
         run: ./gradlew test