use shared gitea runner

.gitea/workflows/build-and-push-image.yml

@@ -14,7 +14,7 @@ jobs:
       IMAGE_REGISTRY: git.uuard.com
       IMAGE_NAME: nicholas/proving-ground
       IMAGE_TAG: ${{ github.sha }}
-    runs-on: ubuntu-latest
+    runs-on: shared-ci
     steps:
       - name: ⬇️ Checkout repo
         uses: actions/checkout@v4

.gitea/workflows/demo.yml

@@ -4,7 +4,7 @@ on: [workflow_dispatch]
 
 jobs:
   Explore-Gitea-Actions:
-    runs-on: ubuntu-latest
+    runs-on: shared-ci
     steps:
       - run: echo "🎉 The job was automatically triggered by a ${{ gitea.event_name }} event."
       - run: echo "🐧 This job is now running on a ${{ runner.os }} server hosted by Gitea!"