fix: add shims for browser and change the sts expire time of example …

[PeterRao]

1. add shims for browser
2. change the default sts expire time fo the example project

[codecov-io]

Codecov Report

Merging #316 into master will decrease coverage by 69.52%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           master     #316       +/-   ##
===========================================
- Coverage   96.48%   26.96%   -69.52%     
===========================================
  Files           8        8               
  Lines        1250     1250               
  Branches      245      245               
===========================================
- Hits         1206      337      -869     
- Misses         44      913      +869

Impacted Files	Coverage Δ
lib/bucket.js	11.65% <0%> (-86.55%)	⬇️
lib/object.js	12.54% <0%> (-83.88%)	⬇️
lib/multipart.js	13.04% <0%> (-83.1%)	⬇️
lib/cluster.js	23.07% <0%> (-76.16%)	⬇️
lib/sts.js	28.37% <0%> (-66.22%)	⬇️
lib/wrapper.js	44.44% <0%> (-51.86%)	⬇️
lib/client.js	47.67% <0%> (-45.57%)	⬇️

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[fengmk2]

dist 目录发布到 npm，为什么呢？

[PeterRao]

有部分用户反馈，构建的时候不想用babel-loader什么的转，想直接引用进来。原始的里面有不少es6的语法。

[fengmk2]

好吧，dist 会有多大？

[PeterRao]

未压缩是728K，压缩的是323K

[JacksonTian]

我看了下，觉得 ok。

[fengmk2]

4.11.3