chore: Add basic PR template

[TerryHowe]

What this PR does / why we need it:
Add a PR template so contributors have some guidelines.

[shizhMSFT]

Thank @TerryHowe for contributing the initial PR template.

We do have a reviewing guide that applies to all pull requests. Meanwhile, we follow the conventional commits for the PR titles.

[TerryHowe]

We do have a reviewing guide that applies to all pull requests. Meanwhile, we follow the conventional commits for the PR titles.

These sound like good items to have in the contribution guide, but it isn't entirely clear they should be in the PR template.

[codecov-commenter]

Codecov Report

Merging #778 (e09ca18) into main (d6240d6) will not change coverage.
The diff coverage is n/a.

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@@           Coverage Diff           @@
##             main     #778   +/-   ##
=======================================
  Coverage   55.50%   55.50%           
=======================================
  Files          23       23           
  Lines         935      935           
=======================================
  Hits          519      519           
  Misses        374      374           
  Partials       42       42           

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[TerryHowe]

All subjects update for this repo at least

[FeynmanZhou]

@TerryHowe Thanks for adding a basic PR template. It looks good. Can we add one more question to this template?

[TerryHowe]

@TerryHowe Thanks for adding a basic PR template. It looks good. Can we add one more question to this template?

I added the check boxes you requested. Was there something else? Thanks.

[FeynmanZhou]

LGTM
cc @oras-project/oras-maintainers

[qweeah]

LGTM (and I just applied to all my PRs👍）

[shizhMSFT]

LGTM as a basic PR template