doc: remove first timer badge

PR-URL: #53338
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ulises Gascón <ulisesgascongonzalez@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Filip Skokan <panva.ip@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Marco Ippolito <marcoippolito54@gmail.com>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: Qingyu Deng <i@ayase-lab.com>

doc/contributing/collaborator-guide.md

@@ -51,8 +51,7 @@ request. See [Who to CC in the issue tracker](#who-to-cc-in-the-issue-tracker).
 ### Welcoming first-time contributors
 
 Always show courtesy to individuals submitting issues and pull requests. Be
-welcoming to first-time contributors, identified by the GitHub
-![First-time contributor](../first_timer_badge.png) badge.
+welcoming to first-time contributors, identified by the GitHub **First-time contributor** badge.
 
 For first-time contributors, check if the commit author is the same as the pull
 request author. This way, once their pull request lands, GitHub will show them