add docs

Author: motatoes

docs/ce/reference/digger.yml.mdx

@@ -104,6 +104,7 @@ workflows:
 | auto_merge                  | boolean                                                       | false    | no       | automatically merge pull requests when all checks pass                                                                                 |                                               |
 | auto_merge_strategy         | string                                                        | "squash" | no       | The merge strategy to use while automerging, defaults to "squash". Possible values: 'squash', 'merge' (for merge commits) and 'rebase' | currently only github supported for this flag |
 | pr_locks                    | boolean                                                       | true     | no       | Enable PR-level locking                                                                                                                |                                               |
+| delete_prior_comments       | boolean                                                       | false    | no       | Enables digger to delete previous comments to reduce noise in the PR                                                                   |                                               |
 | projects                    | array of [Projects](/ce/reference/digger.yml#project)         | \[\]     | no       | list of projects to manage                                                                                                             |                                               |
 | generate_projects           | [GenerateProjects](/ce/reference/digger.yml#generateprojects) | {}       | no       | generate projects from a directory structure                                                                                           |                                               |
 | workflows                   | map of [Workflows](/ce/reference/digger.yml#workflows)        | {}       | no       | workflows and configurations to run on events                                                                                          |                                               |