ci: Fix macos build using "macos-latest" instead of obsolete "macos-1…

…0.15"

See https://github.blog/changelog/2022-07-20-github-actions-the-macos-10-15-actions-runner-image-is-being-deprecated-and-will-be-removed-by-8-30-22/

.github/workflows/CI.yml

@@ -12,10 +12,10 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        runs-on: [macos-10.15]
+        runs-on: [macos-latest]
         python-version: [3.7.12, 3.8.12, 3.9.10]
         include:
-          - runs-on: macos-10.15
+          - runs-on: macos-latest
             c-compiler: "clang"
             cxx-compiler: "clang++"
             initial-dashboard-cache: "CMAKE_OSX_DEPLOYMENT_TARGET:STRING=10.13"
@@ -37,11 +37,6 @@ jobs:
       with:
         version: 1.10.0
 
-    - name: Specific XCode version
-      if: matrix.runs-on == 'macos-10.15'
-      run: |
-        sudo xcode-select -s "/Applications/Xcode_11.7.app"
-
     - name: Download dashboard script
       uses: actions/checkout@v3
       with: