V3 of the Api provides a REST interface for this:
POST /repos/:owner/:repo/issues
{
"title": "Found a bug",
"body": "I'm having a problem with this.",
"assignees": [
"octocat"
],
"milestone": 1,
"labels": [
"bug"
]
}
https://developer.github.com/v3/issues/
You can even add an emoji reaction with the GraphQL Api:
https://developer.github.com/v4/mutation/addreaction/
Or a comment:
https://developer.github.com/v4/mutation/addcomment/
I have looked at the mutations available and I can only conclude that you cannot make an issue with the new Api.