ci: Add workaround for Homebrew's python link error

Promoting Homebrew's [email protected] to the default python3 breaks symbolic
links on macOS x86_64.

This change adds a workaround for that issue.

Also see: actions/runner-images#9471 etc.

Author: hebasto

.github/workflows/ci.yml

@@ -96,7 +96,10 @@ jobs:
       - name: Install Homebrew packages
         env:
           HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK: 1
-        run: brew install automake libtool pkg-config gnu-getopt ccache boost libevent miniupnpc libnatpmp zeromq qt@5 qrencode
+        run: |
+          # A workaround for "The `brew link` step did not complete successfully" error.
+          brew install python@3 || brew link --overwrite python@3
+          brew install automake libtool pkg-config gnu-getopt ccache boost libevent miniupnpc libnatpmp zeromq qt@5 qrencode
 
       - name: Set Ccache directory
         run: echo "CCACHE_DIR=${RUNNER_TEMP}/ccache_dir" >> "$GITHUB_ENV"