ci: Add cargo cache steps to android apk build

Former-commit-id: 20e5f49e3e591de733e012edf9481ea7e9c93a39
Former-commit-id: 9134e6ccfedd969ea7d81bd7064d9c94b12ec421

.github/workflows/build.yml

@@ -68,6 +68,23 @@ jobs:
         submodules: recursive
     - name: Install toolchains
       run: rustup target add aarch64-linux-android armv7-linux-androideabi i686-linux-android
+
+    - name: Cache cargo registry
+      uses: actions/cache@v1
+      with:
+        path: ~/.cargo/registry
+        key: ${{ runner.os }}-cargo-registry-${{ hashFiles('**/Cargo.lock') }}
+    - name: Cache cargo index
+      uses: actions/cache@v1
+      with:
+        path: ~/.cargo/git
+        key: ${{ runner.os }}-cargo-index-${{ hashFiles('**/Cargo.lock') }}
+    - name: Cache cargo build
+      uses: actions/cache@v1
+      with:
+        path: target
+        key: ${{ runner.os }}-cargo-build-target-${{ hashFiles('**/Cargo.lock') }}
+
     - name: Build APK
       working-directory: ./platform/android
       run: ./gradlew build