Revert "build-ios: brew upgrade|install cmake"

This reverts commit bd3900e.

See also:

#5822 (comment)

Author: rwgk

.github/workflows/tests-cibw.yml

@@ -42,9 +42,7 @@ jobs:
         submodules: true
         fetch-depth: 0
 
-    - run: |
-        brew update
-        brew upgrade --formula cmake || brew install --formula cmake
+    - run: brew upgrade cmake
 
     - uses: pypa/[email protected]
       env: