Simplified 'provideSomeM'

[andreamarcolin]

This PR aims to simplify the signature of provideSomeM dropping one type variable (R1).

An example of what should be a common scenario when using this API looks like

type MyEnv = FirstModule with SecondModule

def program: ZIO[MyEnv, Throwable, Unit] = ???

def buildEnv: ZIO[FirstModule, Throwable, MyEnv] = ???

where FirstModule and SecondModule (definitions omitted for brevity) are standard ZIO modules as described in this great @jdegoes article

In this case, an attempt to use provideSomeM (e.g. to effectfully build a part of the environment which depends on another part of it) leads to something like this:

program.provideSomeM[FirstModule, Any, Throwable](_ => buildEnv)

or

program.provideSomeM(_: Any => buildEnv)

which is not so clean due to a type variable (R1) which cannot be inferred automatically from buildEnv function (in fact, with R0 AND R1, we have two "environments".

Removing the type variable R1, leads to a cleaner

program.provideSomeM(buildEnv)

This PR originated from a discussion with the community on Gitter, where even @jdegoes was involved:

[regiskuckaertz]

Another case of profunctor awesomeness 🎉

[jdegoes]

Looks awesome! Thank you!

[jdegoes]

Thank you for your first contribution to ZIO! 🎉