Fixed Generic WebHook API Key not working correctly - #1673

Description

closes #1664
Renamed the values.yaml API key authentication to correspond to the name of the key of the secret instead of the value. Changed template and hook.js accordingly

POC:
Create secret:

kubectl create secret generic generic-webhook-credentials -n integration-tests \
--from-literal=headerName='X-Example-Header' \
--from-literal=headerValue='ThisIsAnAPIkeyValue'

Webhook Event:

{
  "event": {
    "method": "POST",
    "path": "/",
    "query": {},
    "client_ip": "192.168.0.1",
    "url": "https://redacted.m.pipedream.net/",
    "headers": {
      "host": "redacted.m.pipedream.net",
      "content-length": "4057",
      "accept": "application/json, text/plain, */*",
      "content-type": "application/json",
      "x-example-header": "ThisIsAnAPIkeyValue",
      "user-agent": "axios/0.27.2"
    },
    "body": {...}
    }
}

Checklist

• Test your changes as thoroughly as possible before you commit them. Preferably, automate your test by unit/integration tests.
• Make sure that all your commits are signed-off and that you are added to the Contributors file.
• Make sure that all CI finish successfully.
• Optional (but appreciated): Make sure that all commits are Verified.