Add Feature for az create service-connection github for Github Enterprise using token

**Is your feature request related to a problem? Please describe.**
A clear and concise description of what the problem is. Ex. I cannot create a project..

**Describe the solution you'd like**
For the command "az devops service-endpoint github create" there is no option to provide GitHub Enterprise Server and authorization using PAT token.
Even by trying to set this up using json code as below, it doesnt configure as GitHub Enterprise
{
"data": {},
"name": "MyGitHubServiceEndpoint",
"type": "GitHub Enterprise Server",
"url": "https://github.orgname.com",
"authorization": {
"parameters": {
"Token": true
},
"scheme": "Token"
},
"isShared": false,
"isReady": true,
"serviceEndpointProjectReferences": [
{
"projectReference": {
"id": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxx",
"name": "ClientDemoGithubSPN"
},
"name": "MyGitHubServiceEndpoint"
}
]
}

**Additional context**
Add any other context or screenshots about the feature request here.