Change moving_average arguments order

[mlouielu]

For consistency about the API arguments order

[codecov-io]

Codecov Report

Merging #3 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master       #3   +/-   ##
=======================================
  Coverage   89.57%   89.57%           
=======================================
  Files          12       12           
  Lines         470      470           
=======================================
  Hits          421      421           
  Misses         49       49

Impacted Files	Coverage Δ
twstock/analytics.py	98.79% <100%> (ø)	⬆️
twstock/legacy.py	95.09% <100%> (ø)	⬆️

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