Adding Develocity input actions

[cdsap]

Adding Develocity input actions.

If an input is configured in the action, it will generate the environment variable, example:

    - name: Setup Gradle
      uses: gradle/actions/setup-gradle@v3
      with:
        develocity-injection-enabled: true
        develocity-url: https://develocity.your-server.com
        develocity-plugin-version: 3.17.4

    - name: Run a Gradle build with Develocity injection enabled from input actions
      run: ./gradlew build

This configuration will create the environment variables:

DEVELOCITY_INJECTION_ENABLED=true
DEVELOCITY_URL=https://develocity.your-server.com
DEVELOCITY_PLUGIN_VERSION=3.17.4

Relation variable-input available:

Variable	Input
DEVELOCITY_INJECTION_ENABLED	develocity-injection-enabled
DEVELOCITY_URL	develocity-url
DEVELOCITY_ALLOW_UNTRUSTED_SERVER	develocity-allow-untrusted-server
DEVELOCITY_CAPTURE_FILE_FINGERPRINTS	develocity-capture-file-fingerprints
DEVELOCITY_ENFORCE_URL	develocity-enforce-url
DEVELOCITY_PLUGIN_VERSION	develocity-plugin-version
DEVELOCITY_CCUD_PLUGIN_VERSION	develocity-ccud-plugin-version
GRADLE_PLUGIN_REPOSITORY_URL	gradle-plugin-repository-url
GRADLE_PLUGIN_REPOSITORY_USERNAME	gradle-plugin-repository-username
GRADLE_PLUGIN_REPOSITORY_PASSWORD	gradle-plugin-repository-password

[bigdaz]

When I performed a proper review, I found some minor code issues. So I've requested these be fixed, plus some documentation updates.
Thanks!

[bigdaz]

This should return a TypeError for any value besides '', 'false' or 'true'. I'll fix this.