Fix query params 'league' and 'nation' used in Core.club()

[yuesong]

This PR fixes query param names used in Core.club() that don't work for FUT 19. An example API call captured in Chrome looks like this:

https://utas.external.s2.fut.ea.com/ut/game/fifa19/club?sort=asc&type=player&level=bronze&team=650&league=10&nation=34&position=RB&start=0&count=91&_=1548437016376

Note the correct league and nation params in the above URL.

[codecov-io]

Codecov Report

Merging #452 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #452   +/-   ##
=======================================
  Coverage   51.72%   51.72%           
=======================================
  Files           9        9           
  Lines         464      464           
  Branches       39       39           
=======================================
  Hits          240      240           
  Misses        221      221           
  Partials        3        3

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[jimmyyou]

I have the same observation. Looking forward to merging this PR.