Migrate off `baseUrl` in `tsconfig.json`

[72636c]

Per Adam Skoufis, baseUrl will be deprecated in TS 6.0 and removed in 7.0 (the golang rewrite): microsoft/typescript-go#1431 (comment).

This is not set in our central configs but is templated for projects:

skuba/template/base/tsconfig.json

Line 3 in 418bfb4

"baseUrl": ".",