build(deps): bump dawidd6/action-send-mail from 4 to 6

Bumps [dawidd6/action-send-mail](https://github.com/dawidd6/action-send-mail) from 4 to 6.
- [Release notes](https://github.com/dawidd6/action-send-mail/releases)
- [Commits](https://github.com/dawidd6/action-send-mail/compare/v4...v6)

---
updated-dependencies:
- dependency-name: dawidd6/action-send-mail
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/ci.yml

@@ -47,7 +47,7 @@ jobs:
 
     - name: Send failure notification
       if: ${{ failure() }}
-      uses: dawidd6/action-send-mail@v4
+      uses: dawidd6/action-send-mail@v6
       with:
         server_address: email-smtp.us-east-1.amazonaws.com
         server_port: 465