Allow to send list as a value for params in ClientSession

[paulefoe]

🐣 Is your feature request related to a problem? Please describe.
In requests you can do something like this:
r.get('https://www.archlinux.org', params={'ids': [1,2,3,4,5,6]})
and the resulting url would be
https://www.archlinux.org/?ids=1&ids=2&ids=3&ids=4&ids=5&ids=6

The current behavior in aiohttp is to raise TypeError

TypeError: Invalid variable type: value should be str or int, got [1, 2, 3, 4, 5] of type <class 'list'>

💡 Describe the solution you'd like
My suggestion is to convert a list like this to list of tuples in the end, i.e.:

params={
   some: 1,
   list_ids: [1,2 ,3 ]
}

would look like this:

[('some', 1), ('list_ids', 1), ('list_ids', 2), ('list_ids', 3)]

📋 Additional context
If the community decides that this is desirable behavior I am more than willing to work on it.

[WolframAlph]

@webknjaz is this the behaviour we want to have?

[webknjaz]

I believe there's been something similar merged into yarl master recently. Check that out first.

[webknjaz]

Try searching and linking related issues and PRs, if you find something.

[paulefoe]

aio-libs/yarl#443
#4714

Yeah, here it is.