Simply, add `DefaultOptions.addResolvers` in project config
or `DefaultOptions.addPluginResolvers` in plugin config to have known
resolvers added by default (snapshot mode sensitive)
The old convention of keeping credentials in ~/.ivy2 isn't recommended anymore,
they can instead go in (customizable) global base location.
The global base defaults to `~/.sbt`, hence credentials go in `~/.sbt/.credentials`
(c.f. `Keys.globalBaseDirectory` and system property `sbt.global.base`)