Unable to upgrade helm plugin

[maver1ck]

I forked helm-diff plugin and trying to upgrade it gives following error.

maverick@CARBON:~/.helm/plugins/helm-diff$ helm plugin install https://github.com/maver1ck/helm-diff/
Downloading https://github.com/databus23/helm-diff/releases/download/v2.9.0%2B2/helm-diff-linux.tgz
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   609    0   609    0     0    396      0 --:--:--  0:00:01 --:--:--   397
100 4776k  100 4776k    0     0   530k      0  0:00:09  0:00:09 --:--:-- 1056k
Preparing to install into /home/maverick/.helm/plugins/helm-diff
helm-diff installed into /home/maverick/.helm/plugins/helm-diff/helm-diff
***
maverick@CARBON:~/.helm/plugins/helm-diff$ helm plugin update diff --debug
[debug] loading installed plugins from /home/maverick/.helm/plugins
Error: Failed to update plugin diff, got error (plugin does not exist)

Output of helm version:

Server: &version.Version{SemVer:"v2.9.1", GitCommit:"20adb27c7c5868466912eebdf6664e7390ebe710", GitTreeState:"clean"}

Output of kubectl version:

Server Version: version.Info{Major:"1", Minor:"9", GitVersion:"v1.9.6", GitCommit:"9f8ebd171479bec0ada837d7ee641dec2f8c6dd1", GitTreeState:"clean", BuildDate:"2018-03-21T15:13:31Z", GoVersion:"go1.9.3", Compiler:"gc", Platform:"linux/amd64"}

Cloud Provider/Platform (AKS, GKE, Minikube etc.):
AWS

[maver1ck]

I think the problem lies here:

maverick@CARBON:~/.helm/cache/plugins/https-github.com-maver1ck-helm-diff-$ git config --get remote.origin.url
https://github.com/maver1ck/helm-diff.git

The folder name is helm-diff.git and then helm is looking for this directory

[pid  2227] newfstatat(AT_FDCWD, "/home/maverick/.helm/plugins/helm-diff.git", 0xc4209cc788, 0) = -1 ENOENT (No such file or directory)
[pid  2227] write(2, "Error: Failed to update plugin d"..., 71Error: Failed to update plugin diff, got error (plugin does not exist)