There is not a specific event which only monitor the pull request event, you can use ‘issue_comment’ instead, it will monitor comment for both issue and pull request. In the job level, use if expression to filter the comment, exclude the comments from issue.
Code sample as below:
name: pull request comment
types: [created, edited, deleted]
if: contains(github.event.comment.html_url, '/pull/') # check if the comments come from pull request, exclude those from issue.
- name: say hello
if: contains(github.event.comment.body, '/support') # check the comment if it contains the keywords
echo say hello
- name: test
if: contains(github.event.comment.body, '/test') # check the comment if it contains the keywords
I tried on my repo, and it works fine.
Note: please use issue_comment in default branch,eg: master branch.