Added a README section on using GitHub Actions to run experiments with a private repo (#665)

* Added a section on using GitHub Actions to run experiments with a private repo

* Applied suggestions from PR comments

* Adjust wording

---------

Co-authored-by: Eric Haag <[email protected]>

Author: ribafish

Diff for: .github/actions/gradle/README.md

@@ -43,6 +43,29 @@ steps:
 Once the workflow has been triggered and finishes executing, you can navigate to the workflow's output and investigate
 the summary produced by the build validation scripts.
 
+#### Usage with a private repository
+
+The first step of each experiment is to clone the repository containing the build to validate.
+If your repository requires authentication to clone, such as a private repository, you can use the [`actions/checkout`](https://github.com/marketplace/actions/checkout) action to perform the clone instead, as it supports cloning from repositories requiring authentication.
+You can then configure value of the `gitRepo` input parameter to the directory containing the local checkout.
+
+```yaml
+steps:
+  - name: Checkout
+    uses: actions/checkout@v4
+    with:
+      path: project-to-validate # Check out the project to a directory named 'project-to-validate'
+  - name: Download latest version of the validation scripts
+    uses: gradle/gradle-enterprise-build-validation-scripts/.github/actions/gradle/download@actions-stable
+    with:
+      token: ${{ secrets.GITHUB_TOKEN }}
+  - name: Run experiment 3
+    uses: gradle/gradle-enterprise-build-validation-scripts/.github/actions/gradle/experiment-3@actions-stable
+    with:
+      gitRepo: "file://$GITHUB_WORKSPACE/project-to-validate" # Use 'project-to-validate' for the experiment
+      tasks: <PROJECT_BUILD_TASK>
+```
+
 ## Configuration cache compatibility
 
 Composite actions that will simplify validating Configuration Cache compatibility 

Diff for: .github/actions/maven/README.md

@@ -35,3 +35,25 @@ steps:
 
 Once the workflow has been triggered and finishes executing, you can navigate to the workflow's output and investigate
 the summary produced by the build validation scripts.
+
+#### Usage with a private repository
+
+The first step of each experiment is to clone the repository containing the build to validate.
+If your repository requires authentication to clone, such as a private repository, you can use the [`actions/checkout`](https://github.com/marketplace/actions/checkout) action to perform the clone instead, as it supports cloning from repositories requiring authentication.
+You can then configure value of the `gitRepo` input parameter to the directory containing the local checkout.
+
+```yaml
+steps:
+  - name: Checkout
+    uses: actions/checkout@v4
+    with:
+      path: project-to-validate # Check out the project to a directory named 'project-to-validate'
+  - uses: gradle/gradle-enterprise-build-validation-scripts/.github/actions/maven/download@actions-stable
+    with:
+      token: ${{ secrets.GITHUB_TOKEN }}
+  - name: Run experiment 2
+    uses: gradle/gradle-enterprise-build-validation-scripts/.github/actions/maven/experiment-2@actions-stable
+    with:
+      gitRepo: "file://$GITHUB_WORKSPACE/project-to-validate" # Use 'project-to-validate' for the experiment
+      goals: <PROJECT_BUILD_GOAL>
+```