Merge branch 'mktgops-socialupdate' into 'master'

rmv social slack channel from list as it has been archived

See merge request gitlab-com/www-gitlab-com!37078

source/handbook/marketing/index.html.md

@@ -553,11 +553,10 @@ We use Slack internally as a communication tool. The Marketing channels are as f
 - `#sdr_amer_central`: Enterprise SDRs for Americas Central (formerly NORAM - US Central)
 - `#sdr_amer_west`: Enterprise SDRs for Americas West (formerly NORAM - US West)
 - `#sdr-conversations`: place for SDR team brainstorm & sharing of ideas
-- `#social`: Twitter, Facebook, and other social media questions?
 - `#support`: Ask any and all technical questions here for a quick response.
 - `#sfdc-users`: Having issues with SFDC? Ask here first.
 - `#swag`: Request or question regarding swag.
-- `#twitter`: Use this channel to suggest we tweet about something.
+- `#social_media`: Use this channel to communicate and coordinate with the Social Media team.
 - `#website`: Discuss topics related to website redesign project
 ### Marketing email alias list