Remove slack from the footer (#168)

* removes references to Slack from the website

Author: mmahmoudian

static/img/icons/slack.svg

@@ -30,7 +30,6 @@
         <a class="d-inline-block m-1" href="https://github.com/flameshot-org"><img class="footer-icon" src="{{ get_url(path='img/icons/github.svg') }}" alt="github logo." width="26" height="26"></a>
         <a rel="me" class="d-inline-block m-1" href="https://fosstodon.org/@flameshot"><img class="footer-icon" src="{{ get_url(path='img/icons/mastodon.svg') }}" alt="mastodon logo." width="26" height="26"></a>
         <a class="d-inline-block m-1" href="https://matrix.to/#/#flameshot-org:matrix.org"><img class="footer-icon" src="{{ get_url(path='img/icons/matrix.svg') }}" alt="matrix logo." width="26" height="26"></a>
-        <a class="d-inline-block m-1" href="https://flameshotworkspace.slack.com/"><img class="footer-icon" src="{{ get_url(path='img/icons/slack.svg') }}" alt="slack logo." width="26" height="26"></a>
       </div>
       <small class="text-white mt-3">Copyright &copy; 2017-2024 Flameshot contributors &bullet; Site design by <a class="cs-link" href="https://github.com/Correct-Syntax">Correct Syntax</a></small>
     </div>