To have a pull request CI workflow that adds comments referring to specific lines of code, you don’t need any special action. Just use straight up bash:
gh api repos/$GITHUB_REPOSITORY/pulls/${{ github.event.pull_request.number }}/comments \
-f body="$TEXT" \
-f path="$FILE_PATH" \
-F line="$LINE_NUMBER" \
-f side="RIGHT" \
-f commit_id="${{ github.event.pull_request.head.sha }}"
Reference: GitHub REST API
To pipe the output from another command to PR comments:
my script outputting filepath + line + comment \
| xargs -n 3 bash -c \
'gh api ...'
And use $0, $1, $2 for the file, line, and text arguments.