chore(deps): update buildkite plugin shellcheck to v1.4.0

Author: renovate[bot]

.buildkite/pipeline.yml

@@ -12,7 +12,7 @@ steps:
 
   - label: ":shell: Shellcheck"
     plugins:
-      - shellcheck#v1.3.0:
+      - shellcheck#v1.4.0:
           files:
             - hooks/**
             - lib/**