ci: add GitHub Packages publishing and fix release permissions

- Add contents: write permission to github-release job
- Add publish-github-packages job using GITHUB_TOKEN (no extra secrets needed)
- Register GitHubPackages Maven repository for all publishable submodules

Author: FitzAfful

.github/workflows/release.yml

@@ -9,6 +9,8 @@ jobs:
   github-release:
     name: Create GitHub Release
     runs-on: ubuntu-latest
+    permissions:
+      contents: write
 
     steps:
       - name: Checkout
@@ -41,8 +43,41 @@ jobs:
             See [CHANGELOG.md](CHANGELOG.md) for what's changed in this release.
           generate_release_notes: true
 
+  publish-github-packages:
+    name: Publish to GitHub Packages
+    runs-on: ubuntu-latest
+    needs: github-release
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v4
+        with:
+          java-version: '17'
+          distribution: 'temurin'
+
+      - name: Set up Gradle
+        uses: gradle/actions/setup-gradle@v4
+
+      - name: Run tests
+        run: ./gradlew test --stacktrace
+
+      - name: Check public API compatibility
+        run: ./gradlew apiCheck
+
+      - name: Publish to GitHub Packages
+        run: ./gradlew publishAllPublicationsToGitHubPackagesRepository --no-configuration-cache
+        env:
+          ORG_GRADLE_PROJECT_githubPackagesUsername: ${{ github.actor }}
+          ORG_GRADLE_PROJECT_githubPackagesPassword: ${{ secrets.GITHUB_TOKEN }}
+
   # Uncomment and configure when Maven Central secrets are set up:
-  # publish:
+  # publish-maven-central:
   #   name: Publish to Maven Central
   #   runs-on: ubuntu-latest
   #   needs: github-release
@@ -53,8 +88,6 @@ jobs:
   #         java-version: '17'
   #         distribution: 'temurin'
   #     - uses: gradle/actions/setup-gradle@v4
-  #       with:
-  #         cache-encryption-key: ${{ secrets.GRADLE_ENCRYPTION_KEY }}
   #     - run: ./gradlew test --stacktrace
   #     - run: ./gradlew apiCheck
   #     - run: ./gradlew publishAllPublicationsToMavenCentralRepository --no-configuration-cache

build.gradle.kts

@@ -13,3 +13,23 @@ apiValidation {
     ignoredProjects += setOf("sample-app")
     nonPublicMarkers += setOf("io.squarescreen.core.ExperimentalSquareScreenApi")
 }
+
+// Register GitHub Packages as a publish target for all submodules that apply the
+// maven-publish plugin. The task `publishAllPublicationsToGitHubPackagesRepository`
+// is automatically generated by Gradle for a repository named "GitHubPackages".
+subprojects {
+    afterEvaluate {
+        extensions.findByType(org.gradle.api.publish.PublishingExtension::class.java)?.apply {
+            repositories {
+                maven {
+                    name = "GitHubPackages"
+                    url = uri("https://maven.pkg.github.com/Perpectiv-Global/square-screen-android-sdk")
+                    credentials {
+                        username = project.findProperty("githubPackagesUsername") as String? ?: ""
+                        password = project.findProperty("githubPackagesPassword") as String? ?: ""
+                    }
+                }
+            }
+        }
+    }
+}