(ci) specify build tools version when signing

r0adkll/sign-android-release#84

.github/workflows/android-master.yml

@@ -29,6 +29,13 @@ jobs:
           mkdir -p ~/.gradle
           cp .github/ci-gradle.properties ~/.gradle/gradle.properties
 
+      - name: Setup build tool version variable
+        shell: bash
+        run: |
+          BUILD_TOOL_VERSION=$(ls /usr/local/lib/android/sdk/build-tools/ | tail -n 1)
+          echo "BUILD_TOOL_VERSION=$BUILD_TOOL_VERSION" >> $GITHUB_ENV
+          echo Last build tool version is: $BUILD_TOOL_VERSION
+
       - name: Set up JDK
         uses: actions/setup-java@v2
         with:
@@ -51,6 +58,8 @@ jobs:
           alias: ${{ secrets.ALIAS }}
           keyStorePassword: ${{ secrets.KEY_STORE_PASSWORD }}
           keyPassword: ${{ secrets.KEY_PASSWORD }}
+        env:
+          BUILD_TOOLS_VERSION: ${{ env.BUILD_TOOL_VERSION }}
 
       - name: Upload APK
         if: "!startsWith(github.ref, 'refs/tags/') && github.repository == 'ivaniskandar/shouko' && github.event_name == 'push'"