Fix `./gradlew` wrapper run issue in GitHub workflow

Whenever `./gradlew` is used from github workflows, it always gives this error

```
Run ./gradlew build
Error: Could not find or load main class org.gradle.wrapper.GradleWrapperMain
Caused by: java.lang.ClassNotFoundException: org.gradle.wrapper.GradleWrapperMain
```

Find a fix and update workflows to use `./gradlew` if the fix works.