Fix: Ignore other users' comments

[rcowsill]

Other users can post comments containing the header text that findPreviousComment searches for. Doing so can make this action update/recreate/delete the wrong message. Generally it's not a big problem, but in some cases it can be used to inject arbitrary content into the comment made by the action.

This PR makes findPreviousComment only return comments made by the current user, based on the GITHUB_TOKEN (usually github-actions[bot])

[github-actions]

> sticky-pull-request-comment@2.0.1 all /home/runner/work/sticky-pull-request-comment/sticky-pull-request-comment
> npm run build && npm run format && npm run lint && npm run package && npm test


> sticky-pull-request-comment@2.0.1 build /home/runner/work/sticky-pull-request-comment/sticky-pull-request-comment
> tsc


> sticky-pull-request-comment@2.0.1 format /home/runner/work/sticky-pull-request-comment/sticky-pull-request-comment
> prettier --write **/*.ts

__tests__/comment.test.ts 335ms
__tests__/config.test.ts 67ms
src/comment.ts 44ms
src/config.ts 25ms
src/main.ts 19ms

> sticky-pull-request-comment@2.0.1 lint /home/runner/work/sticky-pull-request-comment/sticky-pull-request-comment
> eslint src/**/*.ts


> sticky-pull-request-comment@2.0.1 package /home/runner/work/sticky-pull-request-comment/sticky-pull-request-comment
> ncc build --source-map --license licenses.txt

ncc: Version 0.28.6
ncc: Compiling file index.js
 30kB  dist/licenses.txt
 40kB  dist/sourcemap-register.js
219kB  dist/index.js
259kB  dist/index.js.map
289kB  [1739ms] - ncc 0.28.6

> sticky-pull-request-comment@2.0.1 test /home/runner/work/sticky-pull-request-comment/sticky-pull-request-comment
> jest

PASS __tests__/comment.test.ts
  ✓ findPreviousComment (5 ms)
  ✓ deleteComment
  updateComment
    ✓ with comment body (2 ms)
    ✓ without comment body and previous body (1 ms)
  createComment
    ✓ with comment body or previousBody (1 ms)
    ✓ without comment body and previousBody

PASS __tests__/config.test.ts
  ✓ repo (72 ms)
  ✓ header (6 ms)
  ✓ append (9 ms)
  ✓ recreate (4 ms)
  ✓ delete (5 ms)
  ✓ message (5 ms)
  path
    ✓ when exists return content of a file (5 ms)
    ✓ when not exists return null string (6 ms)

Test Suites: 2 passed, 2 total
Tests:       14 passed, 14 total
Snapshots:   0 total
Time:        3.719 s
Ran all test suites.
::error::ENOENT: no such file or directory, open './__tests__/assets/not_exists'

[marocchino]

Thanks!