Bump plugin version in readme

Author: toote

README.md

@@ -10,7 +10,7 @@ For a full list of features see the [Buildkite Plugin Linter cli tool documentat
 steps:
   - label: ":sparkles: Lint"
     plugins:
-      - plugin-linter#v3.1.0:
+      - plugin-linter#v3.2.0:
           id: my-org/my-plugin
 ```