.github/workflows,Makefile: add a build check CI for the new app

Updates tailscale/tailscale#10992

Signed-off-by: James Tucker <james@tailscale.com>

.github/workflows/android.yml

@@ -0,0 +1,34 @@
+name: Android CI
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - '*'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    if: "!contains(github.event.head_commit.message, '[ci skip]')"
+
+    steps:
+
+    - name: Check out code
+      uses: actions/checkout@v3
+    - uses: actions/setup-go@v5
+      with: 
+        go-version-file: 'go.mod'
+    - name: Switch to Java 17 # Note: 17 is pre-installed on ubuntu-latest
+      uses: actions/setup-java@v3
+      with:
+        distribution: 'temurin'
+        java-version: '17'
+
+    - name: Build APKs
+      run: make tailscale-new-debug.apk tailscale-new-fdroid.apk
+
+    - name: Run tests
+      run: make test

.github/workflows/build-legacy.yml

@@ -1,4 +1,4 @@
-name: Build Debug APK
+name: Build Legacy Debug APK
 
 on:
   push:
@@ -27,5 +27,5 @@ jobs:
         distribution: 'temurin'
         java-version: '17'
 
-    - name: Build APK
+    - name: Build Legacy APK
       run: make tailscale-debug.apk

Makefile

@@ -159,14 +159,19 @@ tailscale-fdroid.apk: $(AAR)
 	(cd android_legacy && ./gradlew test assembleFdroidDebug)
 	mv android_legacy/build/outputs/apk/fdroid/debug/android_legacy-fdroid-debug.apk $@
 
-tailscale-new-fdroid.apk: $(AAR)
+tailscale-new-fdroid.apk: $(AAR_NEXTGEN)
 	(cd android && ./gradlew test assembleFdroidDebug)
 	mv android/build/outputs/apk/fdroid/debug/android-fdroid-debug.apk $@
 
-tailscale-new-debug: $(AAR)
+tailscale-new-debug.apk: $(AAR_NEXTGEN)
 	(cd android && ./gradlew test assemblePlayDebug)
 	mv android/build/outputs/apk/play/debug/android-play-debug.apk $@
 
+tailscale-new-debug: tailscale-new-debug.apk
+
+test: $(AAR_NEXTGEN)
+	(cd android && ./gradlew test)
+
 $(RELEASE_AAB): $(AAR)
 	(cd android_legacy && ./gradlew test bundlePlayRelease)
 	mv ./android_legacy/build/outputs/bundle/playRelease/android-play-release.aab $@