Bump helm-diff version to 3.9.9 (#637)

Signed-off-by: yxxhero <[email protected]>

Author: yxxhero

plugin.yaml

@@ -1,7 +1,7 @@
 name: "diff"
 # Version is the version of Helm plus the number of official builds for this
 # plugin
-version: "3.9.8"
+version: "3.9.9"
 usage: "Preview helm upgrade changes as a diff"
 description: "Preview helm upgrade changes as a diff"
 useTunnel: true