Fix calling macros with kwargs

[leromarinvit]

The kwargs variable currently contains the named parameters listed in a macro's definition, whereas the Jinja documentation says:

Like varargs but for keyword arguments. All unconsumed keyword arguments are stored in this special variable.

python-jinja2 behaves accordingly as well.

[codecov-io]

Codecov Report

Merging #208 into master will increase coverage by 0.04%.
The diff coverage is 100%.

@@             Coverage Diff              @@
##             master     #208      +/-   ##
============================================
+ Coverage      71.3%   71.35%   +0.04%     
- Complexity     1351     1352       +1     
============================================
  Files           215      215              
  Lines          4280     4280              
  Branches        682      682              
============================================
+ Hits           3052     3054       +2     
+ Misses          986      985       -1     
+ Partials        242      241       -1

Impacted Files	Coverage Δ	Complexity Δ
...java/com/hubspot/jinjava/lib/fn/MacroFunction.java	96.42% <100%> (ø)	9 <0> (ø)	⬇️
...hubspot/jinjava/el/ext/AbstractCallableMethod.java	88.23% <0%> (+5.88%)	11% <0%> (+1%)	⬆️

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