Add smoke-build CI workflow (#169)

This adds a workflow into PRs to build the iOS and Android apps, just to verify that they aren't completely broken / unable to build. They're debug builds, so it won't completely mirror the release build, but that allows us to avoid getting signing keys in the workflow.

.github/workflows/flutterfmt.yml

@@ -24,4 +24,4 @@ jobs:
         uses: actions/checkout@v3
 
       - name: Check formating
-        run: dart format -l120 lib/ --set-exit-if-changed --suppress-analytics --output none
+        run: dart format -l120 lib/ --set-exit-if-changed --suppress-analytics --output none

.github/workflows/smoke.yml

@@ -0,0 +1,74 @@
+# This workflow builds the iOS and Android apps, just to check they build without error
+
+name: Smoke build
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  build-android:
+    name: Android
+    runs-on: macos-latest
+    steps:
+      - name: Set up Go 1.22
+        uses: actions/setup-go@v4
+        with:
+          go-version: "1.22"
+
+      - uses: actions/setup-java@v2
+        with:
+          distribution: 'zulu'
+          java-version: '17'
+
+      - name: Install flutter
+        uses: subosito/flutter-action@v2
+        with:
+          flutter-version: '3.24.1'
+
+      - name: Check out code
+        uses: actions/checkout@v3
+
+      - name: install dependencies
+        env:
+          TOKEN: ${{ secrets.MACHINE_USER_PAT }}
+        run: |
+          go install golang.org/x/mobile/cmd/gomobile@latest
+          gomobile init
+          flutter pub get
+          touch env.sh
+
+      - name: Build Android debug
+        run: flutter build appbundle --debug
+
+  build-ios:
+    name: iOS
+    runs-on: macos-latest
+
+    steps:
+      - name: Set up Go 1.22
+        uses: actions/setup-go@v4
+        with:
+          go-version: "1.22"
+
+      - name: Install flutter
+        uses: subosito/flutter-action@v2
+        with:
+          flutter-version: '3.24.1'
+
+      - name: Check out code
+        uses: actions/checkout@v3
+
+      - name: install dependencies
+        run: |
+          go install golang.org/x/mobile/cmd/gomobile@latest
+          gomobile init
+          flutter pub get
+          touch env.sh
+      
+      - name: Build iOS
+        run: |
+          cd ios
+          pod install
+          xcodebuild -workspace Runner.xcworkspace -scheme Runner -configuration Release clean archive CODE_SIGN_IDENTITY="" CODE_SIGNING_REQUIRED=NO CODE_SIGNING_ALLOWED=NO -archivePath "build/MobileNebula.xcarchive"

nebula/Makefile

@@ -9,7 +9,7 @@ clean:
 
 mobileNebula.aar: *.go go.sum
 	go get -d golang.org/x/mobile/cmd/gomobile
-	gomobile bind -trimpath -v --target=android -androidapi 26
+	gomobile bind -trimpath -v --target=android -androidapi=26
 
 MobileNebula.xcframework: *.go go.sum
 	go get -d golang.org/x/mobile/cmd/gomobile