Fix multiple bugs in arrow.get() tzinfo kwarg handling

[systemcatch]

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Description of Changes

The tzinfo kwarg should now be handled correctly rather than being dropped.

fixes #944

[codecov]

Codecov Report

Merging #968 (4d65c00) into master (fe1aaae) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #968   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           10        10           
  Lines         2036      2036           
  Branches       328       328           
=========================================
  Hits          2036      2036           

Impacted Files	Coverage Δ
arrow/factory.py	100.00% <100.00%> (ø)

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[jadchaar]

LGTM, but I think this is a more widespread issue @systemcatch. We should be passing along the tz object in all of these other factory methods as well:

arrow/arrow/factory.py

Lines 234 to 247 in 08705bc

	elif isinstance(arg, Arrow):
	return self.type.fromdatetime(arg.datetime)
	# (datetime) -> from datetime.
	elif isinstance(arg, datetime):
	return self.type.fromdatetime(arg)
	# (date) -> from date.
	elif isinstance(arg, date):
	return self.type.fromdate(arg)
	# (tzinfo) -> now, @ tzinfo.
	elif isinstance(arg, dt_tzinfo):
	return self.type.now(arg)

(and maybe more!). Weird this has not come up until now, but we may need to apply this change to a bunch of factory methods. Thoughts?

[systemcatch]

Hey @jadchaar I agree with you on the Arrow one to avoid this bug below.

>>> arw=arrow.Arrow(2021, 4, 29, 22, 7, tzinfo="America/Chicago")
>>> arw
<Arrow [2021-04-29T22:07:00-05:00]>
>>> arrow.get(arw, tzinfo="Europe/London")
<Arrow [2021-04-29T22:07:00-05:00]>

However the date factory doesn't need it I think and all the others seem correct.

[jadchaar]

@systemcatch I made a few tweaks to comments and made the tzinfo kwarg explicit for the get() factory method in 4d65c00. Let me know what you think!

[systemcatch]

Looks good to me Jad, feel free to merge if you're happy with everything.

[jadchaar]

LGTM