[CI] Fix Minor Issues in dispatch_job.py

There were a couple issues with dispatch_job.py that needed fixing:
1. BUILDBOT_REVISION/Platform were swapped.
2. k8s does not recognize commands in pod definitions, only command.
3. We need to use the function to load the in cluster config rather than load
  what kubectl would use.
4. Move the build step start message into the pod.

Author: boomanaiden154

premerge/buildbot_deployment.yaml

@@ -18,7 +18,7 @@ spec:
       - name: buildbot
         image: ghcr.io/llvm/premerge-buildbot:latest
         env:
-        - name: BUILDBOT_NAME
+        - name: BUILDBOT_USERNAME
           value: ${ buildbot_name }
         - name: BUILDBOT_PASSWORD
           valueFrom:

zorg/buildbot/builders/annotated/premerge/dispatch_job.py

@@ -46,7 +46,7 @@ def start_build(k8s_client, pod_name: str, namespace: str, commands: list[str])
                 {
                     "name": "build",
                     "image": "ghcr.io/llvm/ci-ubuntu-24.04",
-                    "commands": commands,
+                    "command": commands,
                 }
             ],
             "restartPolicy": "Never",
@@ -59,6 +59,7 @@ def start_build_linux(commit_sha: str, k8s_client) -> str:
     """Starts a pod to build/test on Linux at the specified SHA."""
     pod_name = f"build-{commit_sha}"
     commands = [
+        'echo "@@@BUILD_STEP Cloning Repository@@@"'
         "git clone --depth 100 https://github.com/llvm/llvm-project",
         "cd llvm-project",
         f"git checkout ${commit_sha}",
@@ -181,7 +182,7 @@ def print_logs(
 
 
 def main(commit_sha: str, platform: str):
-    kubernetes.config.load_kube_config()
+    kubernetes.config.load_incluster_config()
     k8s_client = kubernetes.client.ApiClient()
     if platform == "Linux":
         pod_name = start_build_linux(commit_sha, k8s_client)
@@ -192,7 +193,6 @@ def main(commit_sha: str, platform: str):
     namespace = PLATFORM_TO_NAMESPACE[platform]
     latest_time = datetime.datetime.min
     v1_api = kubernetes.client.CoreV1Api()
-    print("@@@BUILD_STEP Build/Test@@@")
     while True:
         try:
             pod_finished, latest_time = print_logs(
@@ -219,4 +219,4 @@ def main(commit_sha: str, platform: str):
     if "BUILDBOT_REVISION" not in os.environ:
         logging.fatal("Expected to have BUILDBOT_REVISION environment variable set.")
         sys.exit(1)
-    main(sys.argv[1], os.environ["BUILDBOT_REVISION"])
+    main(os.environ["BUILDBOT_REVISION"], sys.argv[1])