[issues] tag functionality

[dmgorsky]

As of https://docs.github.com/en/rest/issues?apiVersion=2022-11-28 ,
the following URL handlers in octocrab are missing:

• /repos/{owner}/{repo}/milestones
• /orgs/{org}/issues
• /repos/{owner}/{repo}/issues/{issue_number}/events
• /repos/{owner}/{repo}/issues/{issue_number}/assignees/{assignee}
• /repos/{owner}/{repo}/milestones/{milestone_number}/labels
• /user/issues
• /repos/{owner}/{repo}/milestones/{milestone_number}
• /repos/{owner}/{repo}/issues/events
• /issues
• /repos/{owner}/{repo}/issues/events/{event_id}