feat: add support for merge comment

README.md

@@ -12,6 +12,14 @@ This action automatically merges dependabot PRs.
 
 *Optional* An array of packages that you don't want to auto-merge and would like to manually review to decide whether to upgrade or not.
 
+### `merge-method`
+
+*Optional* The merge method you would like to use (squash, merge, rebase). Default to `squash` merge.
+
+### `merge-comment`
+
+*Optional* An arbitrary message that you'd like to comment on the PR after it gets auto-merged. This is only useful when you're recieving too much of noise in email and would like to filter mails for PRs that got automatically merged.
+
 ## Example usage
 
 ```yml

action.yml

@@ -11,6 +11,10 @@ inputs:
     description: "The merge method you would like to use (squash, merge, rebase)"
     required: false
     default: "squash"
+  merge-comment:
+    description: "An arbitrary message that you'd like to comment on the PR after it gets auto-merged"
+    required: false
+    default: ""
 runs:
   using: "node12"
   main: "src/index.js"

src/index.js

@@ -4,7 +4,7 @@ const github = require('@actions/github')
 const { logInfo } = require('./log')
 const { getInputs } = require('./util')
 
-const { GITHUB_TOKEN, MERGE_METHOD, EXCLUDE_PKGS } = getInputs()
+const { GITHUB_TOKEN, MERGE_METHOD, EXCLUDE_PKGS, MERGE_COMMENT } = getInputs()
 
 async function run () {
   try {
@@ -41,6 +41,16 @@ async function run () {
       pull_number: prNumber,
       merge_method: MERGE_METHOD
     })
+
+
+    if (MERGE_COMMENT) {
+      await octokit.issues.createComment({
+        owner,
+        repo,
+        issue_number: prNumber,
+        body: MERGE_COMMENT,
+      });
+    }
   } catch (error) {
     core.setFailed(error.message)
   }

src/util.js

@@ -22,5 +22,6 @@ const getMergeMethod = () => {
 exports.getInputs = () => ({
   GITHUB_TOKEN: core.getInput('github-token', { required: true }),
   MERGE_METHOD: getMergeMethod(),
-  EXCLUDE_PKGS: core.getInput('exclude') || []
+  EXCLUDE_PKGS: core.getInput('exclude') || [],
+  MERGE_COMMENT: core.getInput('merge-comment') || ''
 })