Install appropriate packages for external tests.

Author: ioquatix

.github/workflows/test-external.yaml

@@ -27,10 +27,12 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
-    - uses: ruby/setup-ruby@v1
+    - uses: ruby/setup-ruby-pkgs@v1
       with:
         ruby-version: ${{matrix.ruby}}
         bundler-cache: true
+        apt-get: libvips
+        brew: vips
 
     - name: Run tests
       timeout-minutes: 10