MNT: Add user name and email to Docker to appease git/annex/datalad

[effigies]

Fixing an apparent datalad 0.15 regression that causes failures if user.name and user.email aren't set in Docker containers.

[codecov]

Codecov Report

Merging #3378 (235f580) into master (bb125ab) will increase coverage by 0.87%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3378      +/-   ##
==========================================
+ Coverage   64.23%   65.11%   +0.87%     
==========================================
  Files         307      307              
  Lines       40373    40373              
  Branches     5326     5326              
==========================================
+ Hits        25935    26288     +353     
+ Misses      13385    13014     -371     
- Partials     1053     1071      +18     

Flag	Coverage Δ
unittests	64.83% <ø> (?)

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

Impacted Files	Coverage Δ
nipype/interfaces/spm/preprocess.py	50.44% <0.00%> (+0.88%)	⬆️
nipype/interfaces/freesurfer/model.py	64.19% <0.00%> (+1.12%)	⬆️
nipype/pipeline/engine/utils.py	74.57% <0.00%> (+1.14%)	⬆️
nipype/pipeline/engine/nodes.py	78.63% <0.00%> (+1.26%)	⬆️
nipype/interfaces/freesurfer/preprocess.py	66.37% <0.00%> (+1.66%)	⬆️
nipype/interfaces/cat12/preprocess.py	75.71% <0.00%> (+2.14%)	⬆️
nipype/interfaces/freesurfer/utils.py	63.25% <0.00%> (+2.77%)	⬆️
nipype/interfaces/matlab.py	77.00% <0.00%> (+3.00%)	⬆️
nipype/info.py	87.50% <0.00%> (+3.12%)	⬆️
nipype/utils/config.py	63.24% <0.00%> (+3.78%)	⬆️
... and 11 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update bb125ab...235f580. Read the comment docs.

[effigies]

Quick fix. Merging.