QA Issue Generation

https://gitlab.com/gitlab-org/release-tools/issues/196

Current status:

• !347 (comment 75531349)

TODOS:

• Ensure changes from gitlab-org/release/tasks!30 (merged) are reflected in the QA issue templates for this tool
• Gitlab gem requires a new release. Currently using master branch from Github
• Add docs (gitlab-org/release/docs!32 (merged))

TODOS from example issue generation:

10.8.3 sample

• Fix heredoc indentation
• Cope with gathering MR details from API on a different instance (dev)
• Dev instance usernames are often different for mentions 🤔