ENH: Add support to PANDAS_GBQ_CREDENTIALS_FILE (#86)

[jonathansp]

No description provided.

[codecov-io]

Codecov Report

Merging #87 into master will decrease coverage by 45.4%.
The diff coverage is 27.27%.

@@             Coverage Diff             @@
##           master      #87       +/-   ##
===========================================
- Coverage   73.61%   28.21%   -45.41%     
===========================================
  Files           4        4               
  Lines        1554     1563        +9     
===========================================
- Hits         1144      441      -703     
- Misses        410     1122      +712

Impacted Files	Coverage Δ
pandas_gbq/tests/test_gbq.py	27.8% <16.66%> (-55.2%)	⬇️
pandas_gbq/gbq.py	19.66% <40%> (-55.9%)	⬇️

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[parthea]

Thanks @jonathansp ! Please could you also create an entry in the changelog? https://github.com/pydata/pandas-gbq/blob/master/docs/source/changelog.rst

As an example,

- Environment variable ``PANDAS_GBQ_CREDENTIALS_FILE`` can now be used to override the default location where the BigQuery user account credentials are stored. (:issue:`86`)

[parthea]

storage->store

[jonathansp]

Done.

[parthea]

Thanks @jonathansp !

[jonathansp]

Thanks, @parthea, we really appreciate your work. Do you have a release plan for this change?

[andrelu]

Thanks, @parthea, we really appreciate your work. Do you have a release plan for this change?
+up

[parthea]

@jonathansp I'm hoping to create a new release once #83 is merged (pending approval). It would be great to get your feedback on that PR.

In the interim while we are preparing for the next release, you could install the latest master using:
pip install https://github.com/pydata/pandas-gbq/archive/master.zip