Merge pull request #1 from maver1ck/helm-diff-59

Adding post update hook

Author: maver1ck

plugin.yaml

@@ -8,3 +8,4 @@ useTunnel: true
 command: "$HELM_PLUGIN_DIR/bin/diff"
 hooks:
   install: "$HELM_PLUGIN_DIR/install-binary.sh"
+  update: "$HELM_PLUGIN_DIR/install-binary.sh"helm