Simplify projects/go/config and friends once maint-13.5 is legacy Windows and macOS only
Legacy 13.5 will exist for the following platforms (see: ESR 115 system requirements):
- Windows 7, 8
- macOS 10.12 through 10.15
maint-13.5 currently uses a mix of go 1.20 and 1.21; 1.20 for Windows except for Snowflake which requires 1.21 and 1.21 everywhere else.
go 1.21 is not supported on and is also confirmed to not work on Windows 7 so we're forced to 1.20 here. go 1.21 is only supported on macOS 10.15, while 1.20 requires at least 10.13
Given that go 1.21 isn't supported on old macOS platforms, it looks like we may just gotten lucky to avoid legacy macOS PT crashes ( or nobody is running legacy macOS systems). The latter seems likely given Mozilla's telemetry data.
After the 14.0 release, for maint-13.5 we should drop Snowflake from the Windows tor-expert-bundle and downstream projects. We should leave it for macOS, on the assumption that we either don't have any 10.12-10.14 Snowflake users, or we do and the PT works despite not being supported.
Windows will unconditionally use 1.20, while macOS will unconditionally use 1.21. Both of these major versions are out of support by Google, and will not receive any updates. The relprep.py script does not need to be updated.
We should also gate Snowflake in the Tor Browser UX based on !Windows, but I'll open another issue for this ( tor-browser#41269 )
We should also strip the Snowflake bridges + PTs from the pt_config.json in the tor-expert-bundle