new lhttpc 1.6.2

adding china S3 regions

Merge pull request erlcloud#548 from erlcloud/lhttpc-1.6.1

Update lhttpc dependency to 1.6.1

Merge pull request erlcloud#545 from erlcloud/lhttpc-1.5.7

Pin lhttpc to 1.5.7

Merge pull request erlcloud#543 from egobrain/iso8601

Generate iso8601 optimisation

Merge pull request erlcloud#537 from rjcoelho/master

Default sns scheme to https://

Merge pull request erlcloud#529 from tumdash/step-functions

step functions API

Merge pull request erlcloud#527 from erlcloud/upgrade-rebar-lock-eini

Fix eini reference in rebar.lock file

Merge pull request erlcloud#526 from erlcloud/eini-1.2.5

Update eini to 1.2.5