Run inside docker

.forgejo/workflows/ipv6test.yml

@@ -6,9 +6,11 @@ on:
   workflow_dispatch:
 
 jobs:
-    ipv6:
-        runs-on: ubuntu-24.04
-        steps:
-            - run: |
-                  apt update; apt install --yes curl
-                  curl -s -o /dev/null https://ipv6.google.com
+  ipv6:
+    runs-on: docker
+    container:
+      image: ubuntu:24.04
+    steps:
+      - run: |
+          apt update; apt install --yes curl
+          curl -s -o /dev/null https://ipv6.google.com