[WIP] Update got to v12

[VeskeR]

got@12 is the latest version of got we can update to without making very drastic changes to the codebase.
Installing got@13 will cause our TS import statements to fail with:

Cannot find module 'got' or its corresponding type declarations.
  There are types at 'node_modules/got/dist/source/index.d.ts', but this result could not be resolved under your current 'moduleResolution' setting. Consider updating to 'node16', 'nodenext', or 'bundler'.

and tinkering with module and moduleResolution in tsconfig.json opens up another can of worms which I'm not sure justifies trying to upgrade to got@13

[VeskeR]

If we bundle node.js as an UMD, we will end up with calling require('got') in the UMD header, which inevitably fails with the [ERR_REQUIRE_ESM] error since got@12 is pure ESM and can't be require'd.
So one option is to stop using UMD for node.js bundle and just bundle it as CJS. Then we will only await import('got') whenever we actually need it