README: Update Continuous Integration section with note on setting GitHub Actions permissions

[siropkin]

This update improves the Continuous Integration (CI) documentation by adding a note on configuring GitHub Actions permissions. Without the specified "Read and write permissions" setting, attempts to execute the "Create Pull Request" step in the "Publish Plugin" job may fail, causing the following error:

2024-11-04T14:54:19.0941876Z Switched to a new branch 'changelog-update-v1.4.0'
2024-11-04T14:54:19.1052147Z [changelog-update-v1.4.0 099822b] Changelog update - v1.4.0
2024-11-04T14:54:19.1053680Z  1 file changed, 42 insertions(+), 12 deletions(-)
2024-11-04T14:54:19.6046236Z To https://github.com/siropkin/kursor
2024-11-04T14:54:19.6050386Z  ! [remote rejected] changelog-update-v1.4.0 -> changelog-update-v1.4.0 (refusing to allow a GitHub App to create or update workflow `.github/workflows/build.yml` without `workflows` permission)
2024-11-04T14:54:19.6054203Z error: failed to push some refs to 'https://github.com/siropkin/kursor'
2024-11-04T14:54:19.6081564Z ##[error]Process completed with exit code 1.