Add Slack link to contact information

Updated contact information to include Slack invitation.

Author: RSTZZZ

stamina/index.html

@@ -99,7 +99,7 @@ <h5 style="text-align:center">Suggest a speaker (yourself or others) to give a t
          <h4 style="text-align:center">Research Talk Series 11am ET Tuesdays. Join Us: <a href="https://mcgill.zoom.us/j/87638787060"><img src=https://img.shields.io/badge/Zoom%20meeting%20link-8A2BE2></a></h4>
 
         <h5 style="text-align:center"> Visit our Youtube Playlist for past event recordings: <a href="https://www.youtube.com/playlist?list=PLYndSwsn9HYYl5enbCIXpuFAyqgFDe7_V" target="_blank" rel="noopener noreferrer"><img src="https://img.shields.io/badge/Youtube-Recording-orange"></a> </h5>
-        <h5 style="text-align:center">Questions? Email us at <a href="mailto:stamina@complexdatalab.com">stamina@complexdatalab.com</a></h5>
+        <h5 style="text-align:center">Questions? Email us at <a href="mailto:stamina@complexdatalab.com">stamina@complexdatalab.com</a> or join us on <a href="https://join.slack.com/t/stamina-wg/shared_invite/zt-3z49egjoy-74fWM7aRp4UkhMCwbfmdSA">Slack</a></h5>
         <h5 style="text-align:center">Building our knowledge base on <img src="images/semble-logo.0tc.i06262vfa.svg" style="height: 1lh; vertical-align: middle;"><a href="https://semble.so/profile/stamina-workgroup.bsky.social">Semble</a></h5>
 
   </div>