Change Gradle commands to use the Gradle Wrapper

Example:

name: Java CI

on: [push]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Build with gradle
        run: gradle test

Unix runners:

name: Java CI

on: [push]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Build with gradle
        run: ./gradlew test

Windows Runners:

 name: Java CI

on: [push]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Build with gradle
        run: gradlew test

Same as https://github.com/openrewrite/rewrite-github-actions/issues/57 but with the Gradle Wrapper

Start by comparing this request with the related issue #57 and locate the GitHub Actions recipe that emits Gradle commands. Use the supplied Unix and Windows examples as the expected forms; done means generated workflows use ./gradlew on Unix runners and gradlew on Windows runners.