Add proxy check to test action

.forgejo/workflows/ipv6test.yml

@@ -11,10 +11,17 @@ jobs:
     container:
       image: ubuntu:24.04
     steps:
-      - run: |
+      - name: Check IPv6
+        run: |
           echo "My routes" && cat /proc/net/route
           echo "My routes (IPv6)" && cat /proc/net/ipv6_route
           echo 'Acquire::ForceIPv6 "true";' > /etc/apt/apt.conf.d/1000-force-ipv6-transport
           apt-get update
           apt-get install --yes curl
           curl -s -o /dev/null https://ipv6.google.com
+      - name: Check IPv4 proxy
+        env:
+          HTTP_PROXY: "http://10.0.0.2:8888"
+          HTTPS_PROXY: "http://10.0.0.2:8888"
+        run: |
+          curl -s -o /dev/null https://ipv4.google.com