Use macos-11 for CI

Signed-off-by: falkTX <falktx@falktx.com>

.github/workflows/build.yml

@@ -217,15 +217,11 @@ jobs:
             ${{ github.event.repository.name }}-${{ github.ref_name }}-linux-x86_64.tar.xz
 
   macos-universal:
-    runs-on: macos-10.15
+    runs-on: macos-11
     steps:
       - uses: actions/checkout@v2
         with:
           submodules: recursive
-      - name: Fix up Xcode
-        run: |
-          sudo rm -Rf /Library/Developer/CommandLineTools/SDKs/*
-          sudo xcode-select -s "/Applications/Xcode_12.3.app"
       - name: Build macOS universal
         env:
           CFLAGS: -arch x86_64 -arch arm64 -DMAC_OS_X_VERSION_MAX_ALLOWED=MAC_OS_X_VERSION_10_12 -mmacosx-version-min=10.12 -mtune=generic -msse -msse2