Fix ccache not working in CI

The default `compiler_check` strategy used by ccache was causing a 0% hit rate, as it was using the compiler's "modified time" as part of the hash. Since the script installs dependencies from scratch for every run, mtime was always different, causing different hashes even when source files were unchanged. To avoid this, use the NDK version as part of the hash instead.

.github/workflows/ci.yml

@@ -17,6 +17,8 @@ jobs:
       JVM_OPTS: -Xmx6G
       IS_SKYLINE_SIGNED: ${{ secrets.KEYSTORE != '' }}
       UPLOAD_ARTIFACTS: ${{ github.event_name != 'pull_request' || contains(github.event.pull_request.labels.*.name, 'ci') }}
+      CMAKE_VERSION: "3.22.1"
+      NDK_VERSION: "25.0.8775105"
 
     steps:
       - name: Git Checkout
@@ -27,7 +29,7 @@ jobs:
       - name: Restore CCache
         uses: hendrikmuhs/ccache-action@v1.2
         with:
-          max-size: 2Gi
+          max-size: 3Gi
 
       - name: Restore Gradle Cache
         uses: actions/cache@v3
@@ -45,7 +47,7 @@ jobs:
           ln -s /usr/bin/ninja .
 
       - name: Install CMake & Android NDK
-        run: echo "yes" | $ANDROID_HOME/tools/bin/sdkmanager "cmake;3.22.1" "ndk;25.0.8775105" --channel=3 | grep -v = || true
+        run: echo "yes" | $ANDROID_HOME/tools/bin/sdkmanager "cmake;${{ env.CMAKE_VERSION }}" "ndk;${{ env.NDK_VERSION }}" --channel=3 | grep -v = || true
 
       - name: Decode Keystore
         if: env.IS_SKYLINE_SIGNED == 'true'
@@ -61,7 +63,7 @@ jobs:
           SIGNING_KEY_PASSWORD: ${{ secrets.SIGNING_KEY_PASSWORD }}
           CMAKE_C_COMPILER_LAUNCHER: "ccache"
           CMAKE_CXX_COMPILER_LAUNCHER: "ccache"
-          CCACHE_NOCOMPRESS: "true"
+          CCACHE_COMPILERCHECK: "string:${{ env.NDK_VERSION }}"
         run: ./gradlew --stacktrace --configuration-cache --build-cache --parallel --configure-on-demand assembleFull
 
       - name: Rename APKs (Signed)