chore(deps): update ghcr.io/buildkite/buildkite-mcp-server docker tag to v0.5.11

Author: renovate[bot]

registry/buildkite/spec.yaml

@@ -50,7 +50,7 @@ tags:
   - jobs
   - devops
   - testing
-image: ghcr.io/buildkite/buildkite-mcp-server:0.5.10
+image: ghcr.io/buildkite/buildkite-mcp-server:0.5.11
 permissions:
   network:
     outbound: