a4ad6eda5d
Our fork of https://github.com/Masterminds/squirrel at https://github.com/mattermost/squirrel (previously https://github.com/lieut-data/squirrel) isn't compatible with the upstream project, and causes issues for repositories importing mattermost-server and using squirrel. Sidestep this by adopting the `mattermost/squirrel` fork explicitly. (Downstream repos can either switch, or keep using the upstream version from `Masterminds`.)