ci: use newest intel macos runner image, macos:15-intel

Author: Totto16

.github/workflows/build.yml

@@ -83,7 +83,7 @@ jobs:
 
           - name: MacOS
             os: macos
-            os-version: 13
+            os-version: 15-intel
             arm: false
             shell: bash
             fatal_warnings: true
@@ -166,16 +166,6 @@ jobs:
           version: 14
           platform: x64
 
-      - name: Unbreak Python in GHA (MacOS 13 image)
-        if: matrix.config.os == 'macos' && matrix.config.os-version == 13
-        run: |
-          # TODO: remove this, after it works again
-          # A workaround for "The `brew link` step did not complete successfully" error.
-          # See e.g. https://github.com/Homebrew/homebrew-core/issues/165793#issuecomment-1991817938
-          find /usr/local/bin -lname '*/Library/Frameworks/Python.framework/*' -delete
-          sudo rm -rf /Library/Frameworks/Python.framework/
-          brew install --force python3 && brew unlink python3 && brew unlink python3 && brew link --overwrite python3
-
       - name: Setup Clang (MacOS)
         if: matrix.config.os == 'macos'
         run: |