ci: unused gcc removed from macOS setup

The brew gcc installation is useless, because cmake uses
the clang compiler, which is already present in the system.

Also, the clang is better than gcc for macOS.

Reviewed-by: Sergey Kaplun <skaplun@tarantool.org>
Reviewed-by: Sergey Bronnikov <sergeyb@tarantool.org>
Signed-off-by: Sergey Kaplun <skaplun@tarantool.org>
(cherry picked from commit 7c9cf00)

Author: tmr-g

.github/actions/setup-macos/action.yml

@@ -32,6 +32,9 @@ runs:
         # Try to install the packages either upgrade it to avoid
         # of fails if the package already exists with the previous
         # version.
-        brew install --force cmake gcc make ninja perl ||
-          brew upgrade cmake gcc make ninja perl
+        # Skip GCC installation because the 'builtin' Clang compiler
+        # is already present in the system. It is used by CMake
+        # by default even if GCC is installed.
+        brew install --force cmake make ninja perl ||
+          brew upgrade cmake make ninja perl
       shell: bash