Update buildkite plugin plugin-tester to v1.1.0

Author: renovate[bot]

.buildkite/pipeline.yml

@@ -11,7 +11,7 @@ steps:
 
   - label: ":bash: Tests"
     plugins:
-      - plugin-tester#v1.0.0: ~
+      - plugin-tester#v1.1.0: ~
 
   - wait