Simplify kubernetes dind example allowing for default docker config in workflows (#709)

With this docker clients in workflows can connect on the default socket without needing to change DOCKER_HOST. Startup probe also removes the need for custom shell command.

Co-authored-by: silverwind <me@silverwind.io>
Reviewed-on: https://gitea.com/gitea/runner/pulls/709
Co-authored-by: thisisqasim <40013+thisisqasim@noreply.gitea.com>
Co-committed-by: thisisqasim <40013+thisisqasim@noreply.gitea.com>

examples/kubernetes/rootless-docker.yaml

@@ -4,7 +4,7 @@ metadata:
   name: runner-vol
 spec:
   accessModes:
-    - ReadWriteOnce
+  - ReadWriteOnce
   resources:
     requests:
       storage: 1Gi
@@ -35,7 +35,6 @@ spec:
   strategy: {}
   template:
     metadata:
-      creationTimestamp: null
       labels:
         app: runner
     spec:
@@ -50,7 +49,6 @@ spec:
       - name: runner
         image: gitea/runner:nightly-dind-rootless
         imagePullPolicy: Always
-        # command: ["sh", "-c", "while ! nc -z localhost 2376 </dev/null; do echo 'waiting for docker daemon...'; sleep 5; done; /sbin/tini -- run.sh"]
         env:
         - name: DOCKER_HOST
           value: tcp://localhost:2376