Update README.md (#309)

Author: zgosalvez

README.md

@@ -15,7 +15,7 @@ For more information on these inputs, see the [Workflow syntax for GitHub Action
 - `coverage-files`: The coverage files to scan. For example, `coverage/lcov.*.info`
 - `artifact-name`: The GitHub artifact name of the generated HTML report. For example, `code-coverage-report`. _Note:_ When downloading, it will be extracted in an `html` directory. Optional. Default: `` (Skips uploading of artifacts)
 - `minimum-coverage`: The minimum coverage to pass the check. Optional. Default: `0` (always passes)
-- `github-token`: Set the `${{ secrets.GITHUB_TOKEN }}` token to have the action comment the coverage summary in the pull request. This token is provided by Actions, you do not need to create your own token. Optional. Default: ``
+- `github-token`: Set the `${{ secrets.GITHUB_TOKEN }}` token to have the action comment the coverage summary in the pull request. This token is provided by Actions (after setting permissions - see sample workflow below), you do not need to create your own token. Optional. Default: ``
 - `working-directory`: The working directory containing the source files referenced in the LCOV files. Optional. Default: `./`
 - `title-prefix`: A prefix before the title "LCOV of commit...". Optional. Default: ``
 - `additional-message`: Custom text appended to the code coverage comment in the pull request. Optional. Default: ``
@@ -39,6 +39,8 @@ jobs:
     name: Generate coverage report
     needs: testing
     runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
     steps:
     - name: Checkout code
       uses: actions/checkout@v2