Issue #3504859 by hestenet, pameeela, phenaproxima, thejimbirch: Update...

Issue #3504859 by hestenet, pameeela, phenaproxima, thejimbirch: Update MAINTAINERS.txt to reflect leadership changes, and add an alumni section

MAINTAINERS.txt

@@ -93,7 +93,7 @@ Dashboard
 - Matthew Tift 'mtift' https://www.drupal.org/u/mtift (Lullabot)
 
 Event management
-- Martin Anderson-Clutz 'mandclu' https://www.drupal.org/u/mandclu (Acquia)
+- ?
 
 Gin
 - Sascha Eggenberger 'saschaeggi' https://www.drupal.org/u/saschaeggi (GitLab)
@@ -120,7 +120,7 @@ Privacy
 - Jürgen Haas 'jurgenhaas' https://www.drupal.org/u/jurgenhaas (LakeDrops)
 
 Product marketing
-- Suzanne Dergacheva 'pixelite' https://www.drupal.org/u/pixelite (Evolving Web)
+- Nick Koger 'nkoger' https://www.drupal.org/u/nkoger (Drupal Association)
 
 Publishing Workflows
 - Mohammed Razem 'mohammed j. razem' https://www.drupal.org/u/mohammed-j-razem (Vardot)
@@ -129,5 +129,10 @@ Sitewide SEO
 - Jim Birch 'thejimbirch' https://www.drupal.org/u/thejimbirch (Kanopi Studios)
 - John Doyle '_doyle_' https://www.drupal.org/u/_doyle_ (Digital Polygon)
 
-Trial Experience
-- ?
+Previous Track Leads
+-----------
+Event management
+- Martin Anderson-Clutz 'mandclu' https://www.drupal.org/u/mandclu (Acquia)
+
+Product marketing
+- Suzanne Dergacheva 'pixelite' https://www.drupal.org/u/pixelite (Evolving Web)
\ No newline at end of file