chore(deps): bump github.com/buildkite/go-buildkite/v4

Bumps [github.com/buildkite/go-buildkite/v4](https://github.com/buildkite/go-buildkite) from 4.5.1 to 4.9.0.
- [Release notes](https://github.com/buildkite/go-buildkite/releases)
- [Changelog](https://github.com/buildkite/go-buildkite/blob/main/CHANGELOG.md)
- [Commits](buildkite/go-buildkite@v4.5.1...v4.9.0)

---
updated-dependencies:
- dependency-name: github.com/buildkite/go-buildkite/v4
  dependency-version: 4.9.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

go.mod

@@ -5,7 +5,7 @@ go 1.24.5
 require (
 	github.com/alecthomas/kong v1.12.1
 	github.com/buildkite/buildkite-logs v0.6.1
-	github.com/buildkite/go-buildkite/v4 v4.5.1
+	github.com/buildkite/go-buildkite/v4 v4.9.0
 	github.com/cenkalti/backoff/v5 v5.0.3
 	github.com/mark3labs/mcp-go v0.41.1
 	github.com/mattn/go-isatty v0.0.20

go.sum

@@ -78,8 +78,8 @@ github.com/buger/jsonparser v1.1.1 h1:2PnMjfWD7wBILjqQbt530v576A/cAbQvEW9gGIpYMU
 github.com/buger/jsonparser v1.1.1/go.mod h1:6RYKKt7H4d4+iWqouImQ9R2FZql3VbhNgx27UK13J/0=
 github.com/buildkite/buildkite-logs v0.6.1 h1:5SlAsAFYKy1rl3j7GNldgeOzBMbuKYSgdFlvNnVINEs=
 github.com/buildkite/buildkite-logs v0.6.1/go.mod h1:ejxwp0IDk7Wd0yTH0Cvnw8GgRGnpboe6Up4k9SGmWTg=
-github.com/buildkite/go-buildkite/v4 v4.5.1 h1:45Vgtua5PlZwaaHiI0i7Zz9icOS8PTHkW1YIetpf7Xs=
-github.com/buildkite/go-buildkite/v4 v4.5.1/go.mod h1:fMPu+/7hXzJ7Gy3HpGuVCLgeHqzDdrgHuwQvt8p370I=
+github.com/buildkite/go-buildkite/v4 v4.9.0 h1:/zfx4LiEzPtT/oSciSfRxuvKrPmIk+luv4m0oK0Dy1I=
+github.com/buildkite/go-buildkite/v4 v4.9.0/go.mod h1:DlebrRJqpZttXDjCW+MJ1QyW9AN++ZWt/UbPtKdbSSk=
 github.com/cenkalti/backoff v2.2.1+incompatible h1:tNowT99t7UNflLxfYYSlKYsBpXdEet03Pg2g16Swow4=
 github.com/cenkalti/backoff v2.2.1+incompatible/go.mod h1:90ReRw6GdpyfrHakVjL/QHaoyV4aDUVVkXQJJJ3NXXM=
 github.com/cenkalti/backoff/v5 v5.0.3 h1:ZN+IMa753KfX5hd8vVaMixjnqRZ3y8CuJKRKj1xcsSM=