bump back to 3.12
bump back to 3.12

HubSpot/Singularity,hs-jenkins-bot/Singularity,hs-jenkins-bot/Singularity,HubSpot/Singularity,HubSpot/Singularity,hs-jenkins-bot/Singularity,hs-jenkins-bot/Singularity,HubSpot/Singularity,HubSpot/Singularity,hs-jenkins-bot/Singularity