[Docs] Add CITATION.cff

[mzr1996]

Motivation

Github provides the citation option now, and to use it, we need to add CITATION.cff.

Modification

As the title.

And fix some small typo in setup.py, change author in setup.py. Refers to open-mmlab/mmtracking#253

Use cases

The auto generated bib file:

@misc{MMClassification_Contributors_OpenMMLabs_Image_Classification_2020,
  author = {{MMClassification Contributors}},
  month = {7},
  title = {{OpenMMLab's Image Classification Toolbox and Benchmark}},
  url = {https://github.com/open-mmlab/mmclassification},
  year = {2020}
}

Checklist

Before PR:

• Pre-commit or other linting tools are used to fix the potential lint issues.
• Bug fixes are fully covered by unit tests, the case that causes the bug should be added in the unit tests.
• The modification is covered by complete unit tests. If not, please add more unit test to ensure the correctness.
• The documentation has been modified accordingly, like docstring or example tutorials.

After PR:

• If the modification has potential influence on downstream or other related projects, this PR should be tested with those projects, like MMDet or MMSeg.
• CLA has been signed and all committers have signed the CLA in this PR.

[codecov]

Codecov Report

Merging #428 (6905581) into master (6a0a76a) will increase coverage by 0.28%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #428      +/-   ##
==========================================
+ Coverage   76.73%   77.02%   +0.28%     
==========================================
  Files          97       99       +2     
  Lines        5240     5280      +40     
  Branches      862      866       +4     
==========================================
+ Hits         4021     4067      +46     
+ Misses       1098     1093       -5     
+ Partials      121      120       -1     

Flag	Coverage Δ
unittests	77.02% <ø> (+0.28%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
mmcls/models/classifiers/base.py	69.62% <0.00%> (-1.96%)	⬇️
mmcls/apis/inference.py	19.64% <0.00%> (-0.36%)	⬇️
mmcls/core/visualization/__init__.py	100.00% <0.00%> (ø)
mmcls/core/visualization/image.py	100.00% <0.00%> (ø)
mmcls/models/losses/cross_entropy_loss.py	98.18% <0.00%> (+0.35%)	⬆️

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[Ezra-Yu]

LGTM.