Revert "github-workflows: remove redundant pdftexcmds installation on mac"

This reverts commit 45fe06dca8830a42d81f805a237be57d6f314aff.

Reason for revert: <INSERT REASONING HERE>

Change-Id: I568a62ca1f032c8fa22d3021debc27f491f552c7
diff --git a/.github/workflows/check-mac.yaml b/.github/workflows/check-mac.yaml
index 44f57d0..8ff8cb6 100644
--- a/.github/workflows/check-mac.yaml
+++ b/.github/workflows/check-mac.yaml
@@ -30,6 +30,11 @@
       - uses: r-lib/actions/setup-tinytex@master
         if: contains(matrix.config.args, 'no-manual') == false
 
+      - name: Install system dependencies
+        if: runner.os == 'macOS'
+        run: |
+          tlmgr install pdftexcmds
+
       - name: Cache R packages
         uses: actions/cache@v1
         with: