CI: Added Android GitHub Action

.github/workflows/android_builds.yml

@@ -0,0 +1,72 @@
+name: Android Builds
+on: [push, pull_request]
+
+# Global Cache Settings
+env:
+  SCONS_CACHE_LIMIT: 8192
+
+jobs:
+  android-template:
+    runs-on: "ubuntu-20.04"
+
+    name: Android Template (target=release, tools=no)
+
+    steps:
+      - uses: actions/checkout@v2
+
+      # Azure repositories are not reliable, we need to prevent azure giving us packages.
+      - name: Make apt sources.list use the default Ubuntu repositories
+        run: |
+          sudo cp -f misc/ci/sources.list /etc/apt/sources.list
+          sudo apt-get update
+
+      # install all packages (except scons)
+      - name: Configure dependencies
+        run: |
+         sudo apt-get install openjdk-8-jdk
+         echo "::set-env name=JAVA_HOME::usr/lib/jvm/java-8-openjdk-amd64"
+
+      - name: Install Android Sdk and Ndk
+        run: |
+          echo "::set-env name=PATH::/usr/lib/jvm/java-8-openjdk-amd64/jre/bin:${PATH}"
+          java -version
+          echo "::set-env name=ANDROID_HOME::$(pwd)/godot-dev/build-tools/android-sdk"
+          echo "::set-env name=ANDROID_NDK_ROOT::$(pwd)/godot-dev/build-tools/android-ndk"
+          misc/ci/android-tools-linux.sh
+          source ~/.bashrc
+
+      # Upload cache on completion and check it out now
+      # Editing this is pretty dangerous for windows since it can break and needs properly tested with a fresh cache.
+      # Linux with this will work reliably, so not as bad to edit for Linux.
+      - name: Load .scons_cache directory
+        id: android-template-cache
+        uses: actions/cache@v2
+        with:
+          path: ${{github.workspace}}/.scons_cache/
+          key: ${{runner.os}}-template-${{github.sha}}
+          restore-keys: |
+            ${{runner.os}}-template-${{github.sha}}
+            ${{runner.os}}-template
+            ${{runner.os}}
+
+        # Use python 3.x release (works cross platform)
+      - name: Set up Python 3.x
+        uses: actions/setup-python@v2
+        with:
+          # Semantic version range syntax or exact version of a Python version
+          python-version: '3.x'
+          # Optional - x64 or x86 architecture, defaults to x64
+          architecture: 'x64'
+
+      # You can test your matrix by printing the current Python version
+      - name: Configuring Python packages
+        run: |
+          python -c "import sys; print(sys.version)"
+          python -m pip install scons
+          python --version
+          scons --version
+      - name: Compilation
+        env:
+          SCONS_CACHE: ${{github.workspace}}/.scons_cache/
+        run: |
+          scons -j2 verbose=yes warnings=all werror=yes platform=android target=release tools=no