Check if we can get to opensource.org via curl

.github/workflows/build.yml

@@ -12,6 +12,15 @@ jobs:
     - uses: actions/setup-python@v5
       with:
         python-version: 3.12
+    - name: Try curl to get to opensource.org
+      run: |
+        curl -I https://opensource.org/ \
+          --http1.1 \
+          -H "User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:100.0) Gecko/20100101 Firefox/100.0 Sphinx/7.2.6" \
+          -H "Accept-Encoding: gzip, deflate" \
+          -H "Accept: */*" \
+          -H "Connection: keep-alive"
+
     - name: Install Requirements
       run: |
         pip install --upgrade pip