feat(github): add support for github issue templates

[kennyg]

adds support for github issue templates. Closes #3567. Tested this by setting up a local project and adding this snippet to the .projenrc.ts

new IssueTemplate(project.github!, {
  templates: {
    'bug-report.md': '<!-- Bug report template content -->',
    'feature-request.yml': '<!-- Feature request template content -->',
  },
});

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[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 96.38%. Comparing base (ad20d2c) to head (912ab2a). Report is 112 commits behind head on main.

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #3648 +/- ## ========================================== + Coverage 96.34% 96.38% +0.03% ========================================== Files 192 195 +3 Lines 37696 38200 +504 Branches 3524 3571 +47 ========================================== + Hits 36320 36819 +499 - Misses 1376 1381 +5 ```

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