[CI] Use MacOS universal build instead of 2 builds.

Switch to the now available macOS 11 for building.

.github/workflows/ci.yml

@@ -108,7 +108,7 @@ jobs:
 
   macos:
     name: Build (macOS, Clang)
-    runs-on: macos-10.15
+    runs-on: macos-11
     steps:
       - name: Checkout
         uses: actions/checkout@v2
@@ -133,45 +133,18 @@ jobs:
       - name: Upload artifact
         uses: actions/upload-artifact@v2
         with:
-          name: godot-cpp-macos-x86_64-release
+          name: godot-cpp-macos-universal-release
           path: bin/libgodot-cpp.osx.release.64.a
           if-no-files-found: error
 
       - name: Build test GDNative library
         run: |
-          scons target=release platform=osx bits=64 -j $(sysctl -n hw.logicalcpu) -C test
+          scons target=release platform=osx bits=64 macos_arch=universal -j $(sysctl -n hw.logicalcpu) -C test
 
       - name: Run test GDNative library
         run: |
           ./Godot.app/Contents/MacOS/Godot --path test -s script.gd
 
-  macos-arm64:
-    name: Build (macOS, Clang, cross-compile arm64)
-    runs-on: macos-latest
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-        with:
-          submodules: recursive
-
-      - name: Set up Python (for SCons)
-        uses: actions/setup-python@v2
-        with:
-          python-version: '3.x'
-
-      - name: Install dependencies
-        run: |
-          python -m pip install scons
-
-      - name: Build godot-cpp
-        run: |
-          # The default SDK in github the actions environemnt seems to have problems compiling for arm64.
-          # Use the latest 11.x SDK.
-          SDK_BASE=/Library/Developer/CommandLineTools/SDKs
-          SDK_VER=$(ls $SDK_BASE | grep "MacOSX11." | sort -r | head -n1)
-          echo $SDK_BASE/$SDK_VER/
-          scons target=release generate_bindings=yes macos_arch=arm64 macos_deployment_target=10.15 macos_sdk_path="$SDK_BASE/$SDK_VER/" -j $(sysctl -n hw.logicalcpu)
-
   static-checks:
     name: Static Checks (clang-format)
     runs-on: ubuntu-20.04