Use GitHub Actions instead of AppVeyor for Windows platform

This was based on quarmin's initial configuration, we had compile issues with AppVeyor being super slow and GitHub actions will take less time and also manage a full rebuild in 30 minutes.

This adds cache handling and will work with MSVC and scons 4.0, it will build for every PR submitted to the Godot Engine, and also for the branches specified. I have tested the caching and it seems to be working.

I left the 'publish artefacts' disabled until we can request more storage from Microsoft, 5 GB is far to low for us and we would eat this limit very fast. (it is tested and works fine)

Co-authored-by: Rafał Mikrut <mikrutrafal54@gmail.com>

.github/workflows/main.yml

@@ -0,0 +1,126 @@
+# Engine build CI
+name: Godot CI
+
+on:
+    # will build EVERY pull request
+    pull_request:
+
+    # will only build explicit branches
+    push:
+      branches: [ master, 3.2, 3.1, 3.0 ]
+
+# Global Cache Settings
+# SCONS_CACHE for windows must be set in the build environment
+env:
+  SCONS_CACHE_MSVC_CONFIG: true
+  SCONS_CACHE_LIMIT: 8192
+jobs:
+  windows-editor:
+    # Windows 10 with latest image
+    runs-on: "windows-latest"
+
+    # Windows Editor - checkout with the plugin
+    name: Windows Editor (target=release_debug, tools=yes)
+
+    steps:
+    - uses: actions/checkout@v2
+
+    # 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: windows-editor-cache
+      uses: RevoluPowered/cache@v2.1
+      with:
+        path: /.scons_cache/
+        key: ${{runner.os}}-editor-${{github.sha}}
+        restore-keys: |
+          ${{runner.os}}-editor-${{github.sha}}
+          ${{runner.os}}-editor
+          ${{runner.os}}
+
+    # Use python 3.x release (works cross platform; best to keep self contained in it's own step)
+    - 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' 
+
+    # Setup scons, print python version and scons version info, so if anything is broken it won't run the build.
+    - name: Configuring Python packages
+      run: |
+        python -c "import sys; print(sys.version)"
+        python -m pip install scons pywin32
+        python --version
+        scons --version
+
+    # We should always be explicit with our flags usage here since it's gonna be sure to always set those flags
+    - name: Compilation
+      env:
+        SCONS_CACHE: /.scons_cache/
+      run: |
+        scons -j2 verbose=yes warnings=all werror=yes platform=windows tools=yes target=release_debug
+
+# Build Product Upload (tested and working)
+# sorry this is disabled until github can give us some more space as we would hit our limit very quickly
+# tested this code and it works fine so just enable it to get them back
+#    - name: publishing godot windows-editor
+#      uses: actions/upload-artifact@v1
+#      with:
+#        name: windows-editor (x64)
+#        path: bin/godot.windows.opt.tools.64.exe
+
+
+  windows-template:
+    runs-on: "windows-latest"
+    name: Windows Template (target=release, tools=no)
+
+    steps:
+    - uses: actions/checkout@v2
+
+    # 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: windows-template-cache
+      uses: RevoluPowered/cache@v2.1
+      with:
+        path: /.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 pywin32
+        python --version
+        scons --version
+    - name: Compilation
+      env:
+        SCONS_CACHE: /.scons_cache/
+      run: |
+        scons -j2 verbose=yes warnings=all werror=yes platform=windows target=release tools=no
+
+# Build Product Upload (tested and working)
+# sorry this is disabled until github can give us some more space as we would hit our limit very quickly
+# tested this code and it works fine so just enable it to get them back
+#    - name: publishing godot windows-template
+#      uses: actions/upload-artifact@v1
+#      with:
+#        name: windows-template (x64)
+#        path: bin/godot.windows.opt.64.exe