CI: cache dependencies in makefile

cache both gradle and haveno-specific dependencies when running CI.
windows binaries are built using ./gradlew build directly, since
windows users have to download binaries manually regardless.

.github/workflows/build.yml

@@ -11,9 +11,43 @@ jobs:
   build:
     strategy:
       matrix:
-        os: [ubuntu-latest, windows-latest, macos-latest]
+        os: [ubuntu-latest, macos-latest]
       fail-fast: false
     runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          lfs: true
+      - name: Set up JDK 11
+        uses: actions/setup-java@v2
+        with:
+          java-version: '11'
+          distribution: 'adopt'
+          cache: gradle
+      - name: Pull lfs
+        run: git lfs pull
+      - name: Build with make
+        run: make
+      - name: cache nodes dependencies
+        uses: actions/upload-artifact@v2
+        with:
+          name: cached-localnet
+          path: .localnet
+      - name: Cleanup Gradle Cache
+        # Remove some files from the Gradle cache, so they aren't cached by GitHub Actions.
+        # Restoring these files from a GitHub Actions cache might cause problems for future builds.
+        run: |
+          rm -f ~/.gradle/caches/modules-2/modules-2.lock
+          rm -f ~/.gradle/caches/modules-2/gc.properties
+      - uses: actions/upload-artifact@v2
+        if: failure()
+        with:
+          name: gradlew-report
+          path: 'desktop/build/reports/tests/test/index.html'
+          retention-days: 30
+
+  build-windows:
+    runs-on: windows-latest
     steps:
       - uses: actions/checkout@v2
         with:
@@ -27,9 +61,3 @@ jobs:
         run: git lfs pull
       - name: Build with Gradle
         run: ./gradlew build --stacktrace --scan
-      - uses: actions/upload-artifact@v2
-        if: failure()
-        with:
-          name: gradlew-report
-          path: 'desktop/build/reports/tests/test/index.html'
-          retention-days: 30