MIGRATION: Adjust GitHub issues template

[toddfarmer]

Users attempting to report issues via the Arrow GitHub project see the following options:

If issue tracking for the project is migrated to GitHub issues from ASF Jira, this will need to be adjusted here.

[jorisvandenbossche]

This is essentially a duplicate from https://issues.apache.org/jira/browse/ARROW-18364 and is resolved now?