Merge pull request #472 from h2o/kazuho/macos-ci

GitHub Actions macOS image no longer has pkg-config
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 454ea7b..8b538ad 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -62,7 +62,7 @@
       env:
         OPENSSL: ${{ matrix.openssl }}
       run: |
-        brew install perl libfaketime ${OPENSSL}
+        brew install perl libfaketime pkg-config ${OPENSSL}
         perl -v
         curl -sSfL https://cpanmin.us | perl - -v --notest Scope::Guard Test::TCP