Allow creating a manifest-PR using a comment at a later point

There are some cases where the following happens:
1. You create a draft PR, you don't want to create the manifest PR yet.
2. You have checked the draft PR manually, now you want a manifest-PR

This commit adds the possibility to create the manifest PR upon a
comment to a PR.

Signed-off-by: Rubin Gerritsen <rubin.gerritsen@nordicsemi.no>

Author: rugeGerritsen

action.yml

@@ -15,6 +15,10 @@ inputs:
       required: false
       type: string
       default: manifest-pr-skip
+    create-pr-comment-string:
+      required: false
+      type: string
+      default: 'action-manifest-pr please create manifest-PR'
     rebase-comment-string:
       required: false
       type: string
@@ -119,7 +123,10 @@ runs:
 
 # create actual manifest PR
     - name: Commit changed west.yml and create PR
-      if: ${{ github.event.action == 'opened' }}
+      if: ${{ github.event.action == 'opened' }} ||
+          (  ${{ github.event.issue.pull_request }} &&
+             ${{ github.event.issue_comment.created }}
+             contains(github.event.issue_comment.created.comment, inputs.create-pr-comment-string)) )
       shell: bash
       env:
         GH_TOKEN: ${{ inputs.token }}