Support IProgress in ParallelForEachAsync

[Misiu]

Consider adding IProgress to ParallelForEachAsync
I'm currently using this method, but I'd like to switch to Your library.

Will this change be ok?

[kind-serge]

Hi @Misiu , thanks for submitting the PR!
Give me a few days to review this - have important things to do this week.

[Misiu]

@TYROTOXIN no worries :)
Please consider merging this PR, new csproj format would help a lot.

I think this library will be more wonderful when supporting more IProgress object