Update `Client` in order to use request body instead of query string with `post()` and `put()` methods

[phansys]

Q	A
Branch	master
Bug fix?	yes
New feature?	no
BC breaks?	no
Deprecations?	no
Tests pass?	yes
Fixed tickets	n/a
License	MIT
Doc PR	n/a

These changes prevents errors like "zoho Internal API error: 414 Request-URI Too Large", since the whole request was encoded and sent as query string.

Also, the way in which the array concat was done (+ operator order) in Client methods is updated in order to use Client::getParams() as a source for default values, but allowing them to be overridden by the method's arguments.

The call to \json_encode() was replaced by \GuzzleHttp\json_encode() at Client::getParams(), in order to prevent this kind of errors with URI sizes.

[codecov[bot]]

Codecov Report

Merging #23 into master will decrease coverage by 0.06%. The diff coverage is 0%.

@@             Coverage Diff             @@
##             master     #23      +/-   ##
===========================================
- Coverage      6.82%   6.76%   -0.07%     
  Complexity      112     112              
===========================================
  Files            12      12              
  Lines           205     207       +2     
===========================================
  Hits             14      14              
- Misses          191     193       +2

Impacted Files	Coverage Δ	Complexity Δ
src/Client.php	0% <0%> (ø)	17 <0> (ø)	:arrow_down:

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[mrVrAlex]

Maybe have sense write unit tests for getList(), post(), put(), get() methods with httpClient mock in this PR?

[phansys]

@shandyDev, since these changes are related on how the arguments are provided to the base client (Guzzle), I don't know how to add tests to this library, since these arguments aren't handled by the library itself. Have you any thought about this?

[mrVrAlex]

Ok I merged it. Unit test I will try write later on this week, separatly.