Enable release/update pipeline in Mullvad Browser

Targets:

12.0a6 (03-17) build should have updater enabled
12.0a7 (03-24) build should include mars and update responses
- once deployed 12.0a6 should be able to update to 12.0a7
12.0a8 (03-31) tentatively the last scheduled alpha before release
12.0.4 (04-??) first public stable release
12.5a4 (04-??) first public alpha release

Edited Mar 15, 2023 by morgan

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information