Add a workflow to upload baseline images as a release asset

.github/workflows/release-baseline-images.yml

@@ -0,0 +1,42 @@
+# Upload the archive of baseline images as release asset
+
+name: Upload baseline images
+
+# Only run for releases
+on:
+  release:
+    types:
+      - published
+
+jobs:
+  upload-baseline:
+    name: Upload baseline images
+    runs-on: ubuntu-latest
+    if: github.repository == 'seisman/pygmt'
+
+    steps:
+    - name: Checkout
+      uses: actions/[email protected]
+
+    - name: Setup data version control (DVC)
+      uses: iterative/[email protected]
+
+    - name: Pull baseline image data from dvc remote
+      run: |
+        dvc pull
+        ls -lhR pygmt/tests/baseline/
+
+    - name: Create the baseline image asset in zip format
+      run: |
+        mkdir baseline-images
+        mv pygmt/tests/baseline/*.png baseline-images/
+        zip -r baseline-images.zip baseline-images
+
+    - name: Upload baseline image as a release asset
+      uses: shogo82148/[email protected]
+      with:
+        upload_url: ${{ github.event.release.upload_url }}
+        asset_path: baseline-images.zip
+
+
+