ci: use docker runner label to match self-hosted runner

.github/workflows/build.yml

@@ -7,7 +7,7 @@ on:
 jobs:
   build:
     name: Build App
-    runs-on: media-server
+    runs-on: docker
 
     steps:
       - name: Checkout

.github/workflows/release-webhook.yml

@@ -11,7 +11,7 @@ on:
 jobs:
   release-webhook:
     name: Send Release Webhook
-    runs-on: media-server
+    runs-on: docker
 
     steps:
       - name: Send release notification webhook

.github/workflows/validate-pr-title.yml

@@ -14,7 +14,7 @@ on:
 jobs:
   main:
     name: Validate PR title
-    runs-on: media-server
+    runs-on: docker
     permissions:
       pull-requests: read
     steps: