Update Issue Template scheme

[josh-hadley]

ISSUE_TEMPLATE.md currently shows a message that we are "using an old version of issue templates" and that we should update "to the new issue template workflow" which allows multiple templates for different issue types. More details here.

We should consider updating starter-repo to use this new scheme.

[debanjana-a11y]

The "Set up templates" is missing in my forked "starter-repo". I guess it is allowed only for the repo owner so I cant contribute here :(