add plugin label to builder (apple#1443)

## Type of Change
- [ ] Bug fix
- [x] New feature  
- [ ] Breaking change
- [ ] Documentation update

## Motivation and Context
add plugin label to builder

## Testing
- [ ] Tested locally
- [ ] Added/updated tests
- [ ] Added/updated docs

Author: realrajaryan

Sources/ContainerCommands/Builder/BuilderStart.swift

@@ -246,7 +246,10 @@ extension Application {
 
             var config = ContainerConfiguration(id: Builder.builderContainerId, image: imageDesc, process: processConfig)
             config.resources = resources
-            config.labels = [ResourceLabelKeys.role: ResourceRoleValues.builder]
+            config.labels = [
+                ResourceLabelKeys.plugin: "builder",
+                ResourceLabelKeys.role: ResourceRoleValues.builder,
+            ]
             config.capAdd = ["ALL"]
             config.mounts = [
                 .init(