v1.6.0

JuliaZH v1.6.0

Diff since v1.5.4

Closed issues:

• 安装juliazh后依然是英文文档，版本1.5.3，win10 (#119)
• add mirrors: sustech and NJU (#120)

Merged pull requests:

• use PkgServerClient to choose the best mirror server as pkg server (#121) (@johnnychen94)
• OSPP 2021: sync manual translation v1.7 from transfix (#122) (@johnnychen94)
• set up Github Action CI (#123) (@johnnychen94)
• Set up pdf CI using github actions (#124) (@johnnychen94)
• 在文档首页添加镜像站的汇总链接 (#125) (@johnnychen94)
• update translated docs (#126) (@johnnychen94)
• update Chinese translation (#127) (@johnnychen94)
• make 1.6.0 release (#128) (@johnnychen94)