Update github actions

Motivation

I understand the development of arara happens in GitLab, but since two GitHub Actions workflows are both turned on, it seems to me that fixing build on github still makes a bit of sense. At least it saves me from receiving "Run fails" emails when I push to my GitHub fork. Currently this step of workflow gradle.yml

    - uses: eskatos/gradle-command-action@v1
      with:
        gradle-version: current
        arguments: build

fails with two java.lang.AbstractMethodErrors on windows-latest, see run 3573479482 in arara's github mirror repo.

Explanation

• Update actions
  • You can check the action renaming by visiting https://github.com/eskatos/gradle-command-action and seeing it redirects to https://github.com/gradle/gradle-build-action.
  • Add a new required input (distribution: adopt) for action setup-java@v2. Here adopt stands for AdoptOpenJDK Hotspot, see list of supported distributions.
  • Add github dependabot to receive notifications (currently only support github PRs) about future action updates, see its doc.
• Fix build
  All the changes above don't fix the build. Then I tried replacing current two build steps with a use: gradle/gradle-build-action@v2 step without running any command and a (new) step runs ./gradlew --no-daemon :cli:shadowJar, copied from flake.nix. It finally passed, see run 3608411379 in my github fork.