Remove workaround for macOS builds due to pkg-config issues (#1202)

In November, macOS runners had an issue with the `pkg-config` package
and we introduced a workaround:
#1158

We see now that the fix has been released and we should no longer need
the workaround: actions/runner-images#10984.

### Does this change impact existing behavior?

No, CI change only.

### Does this change need a changelog entry?

No.

---

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license and I agree to the terms of
the [Developer Certificate of Origin
(DCO)](https://developercertificate.org/).

Signed-off-by: Daniel Carl Jones <[email protected]>

.github/workflows/tests.yml

@@ -65,15 +65,8 @@ jobs:
       with:
         submodules: true
     - name: Install dependencies
-      # Temporarily uninstall [email protected] in order to work around a homebrew issue with pkg-config
-      # on github runners: https://github.com/actions/runner-images/issues/10984.
-      # Once the runners' image is updated (tracking https://github.com/actions/runner-images/pull/11011),
-      # we could revert to just:
-      #   brew update > /dev/null && brew install pkgconfig
       run: |
-          brew update
-          brew uninstall --ignore-dependencies --force [email protected]
-          brew install pkgconf
+        brew update > /dev/null && brew install pkgconfig
     - name: Install fuse
       run: |
         brew install --cask macfuse