Trouble with using the websocket plugin

I am having some trouble using the serverless-websockets-plugin. I am following the instructions written up here. But when I deploy, I get this error.

Serverless plugin "serverless-websocket-plugin" not found. Make sure it's installed and listed in the "plugins" section of your serverless config file.

I know there are multiple topics here with a similar issue, but none of the solutions in those topics seems to work for me :crying_cat_face:

I have the plugin installed using

npm i serverless-websockets-plugin --save 

I can see the plugin listed in my package.json file.

"dependencies": {
    "serverless-websockets-plugin": "^1.0.0"

I can see the plugin listed if I do an npm list | grep websocket

└─┬ serverless-websockets-plugin@1.0.0

And finally, I can require the plugin on node

(aws) ➜  orders git:(dev) ✗ node 
Welcome to Node.js v14.3.0.
Type ".help" for more information.
> require('serverless-websockets-plugin')
[Function: ServerlessWebsocketsPlugin]

Here is how I have listed the plugins on the serverless.yaml file

 - serverless-python-requirements
 - serverless-websocket-plugin

Question: How do I deploy with the serverless-websocket-plugin plugin ?