安装Rebar时出现真实性验证错误的排查求助

问题现象 #

使用Elixir 1.8.1在Gitlab CI环境安装Rebar时，触发以下错误：

* creating /root/.mix/archives/hex-2.0.6
* creating /root/.mix/rebar
** (Mix) Could not install Rebar because Mix could not verify authenticity of metadata file at "https://repo.hex.pm/installs/rebar3-1.x.csv". This may happen because a proxy or some entity is interfering with the download or because you don't have a public key to verify the download.
You may try again later or check if a new public key has been released in our public keys page: https://repo.hex.pm/installs/public_keys.html

但2.5小时前相同的CI流程运行正常，日志显示：

* creating /root/.mix/archives/hex-2.0.6
* creating /root/.mix/rebar
* creating /root/.mix/rebar3

我方未做任何代码或CI配置变更，疑问：此问题是Gitlab平台问题、Rebar3新版本发布导致，还是hex仓库的问题？

问题结论更新 #

经确认，问题根源出在hex服务端，相关社区讨论已存在：

• GitHub上的Elixir项目Issue
• Elixir官方论坛的相关讨论帖

内容的提问来源于stack exchange，提问作者kepler