Update travis and appveyor test script

[codecov-io]

Codecov Report

Merging #148 into master will increase coverage by 0.03%. The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #148      +/-   ##
==========================================
+ Coverage   95.87%   95.91%   +0.03%     
==========================================
  Files          53       53              
  Lines        2597     2597              
  Branches      239      239              
==========================================
+ Hits         2490     2491       +1     
  Misses         77       77              
+ Partials       30       29       -1

Impacted Files	Coverage Δ
...dk-core/Auth/InstanceProfileCredentialsProvider.cs	100% <0%> (+2.77%)	:arrow_up:

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[JacksonTian]

squash 。。不要 merge

[AxiosLeo]

我是选择的squash and merge, 好像没有仅squash的选项。