add julia 1.3 to CI

[codecov[bot]]

Codecov Report

Merging #140 (a49f866) into master (29b2fa3) will increase coverage by 0.02%. Report is 9 commits behind head on master. The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #140      +/-   ##
==========================================
+ Coverage   93.60%   93.63%   +0.02%     
==========================================
  Files          25       25              
  Lines        3098     3111      +13     
==========================================
+ Hits         2900     2913      +13     
  Misses        198      198              

see 3 files with indirect coverage changes

:mega: We’re building smart automated test selection to slash your CI/CD build times. Learn more

[david-pl]

Superseded by #141