First cut at actions for dependency-graph

- Dependency graph init-script references published version of plugin jar.
- `dependency-graph-generate` action will:
     - Provision Gradle if required
     - Execute Gradle with dependency-graph plugin to generate graph JSON
     - Upload dependency-graph JSON file as workflow artifact
- `dependency-graph-submit` action will:
    - Download dependency-graph JSON artifact
    - Submit the graph via the GitHub dependency submission API

actions/dependency-graph-generate/action.yml

@@ -0,0 +1,19 @@
+name: "Dependency Graph Generate"
+description: Calculates the complete dependency graph for the repository, saving it as a JSON artifact.
+
+inputs:
+  gradle-version:
+    description: Gradle version to use. If specified, this Gradle version will be downloaded, added to the PATH and used for invoking Gradle.
+    required: false
+
+  gradle-executable:
+    description: Path to the Gradle executable. If specified, this executable will be added to the PATH and used for invoking Gradle.
+    required: false
+
+  build-root-directory:
+    description: Path to the root directory of the build. Default is the root of the GitHub workspace.
+    required: false
+
+runs:
+  using: 'node16'
+  main: '../../dist/dependency-graph-generate/index.js'

actions/dependency-graph-submit/action.yml

@@ -0,0 +1,12 @@
+name: "Dependency Graph Submit"
+description: Retrieves a previously created dependency graph JSON and submits via the GitHub Dependency Submission API.
+
+inputs:
+  github-token:
+    description: The GitHub token used to authenticate when submitting via the Dependency Submission API.
+    default: ${{ github.token }}
+    required: false
+
+runs:
+  using: 'node16'
+  main: '../../dist/dependency-graph-submit/index.js'