v3.0.0-beta.6

First release of gradle/actions, which is a replacement for gradle/gradle-build-action and so much more.

Included in this release:

• gradle/actions/setup-gradle : drop-in replacement for gradle/gradle-build-action
• gradle/actions/dependency-submission: specialized action for generating and submitting dependency graphs

These actions be referenced as gradle/actions/<action-name>@v3.0.0-beta.6 or gradle/actions/<action-name>@v3-beta.

There are no functional changes between gradle/gradle-build-action@v3.0.0-beta.5 and gradle/actions/setup-gradle@v3.0.0-beta.6.