完美解决ubuntu:签名无效 KEYEXPIRED、EXPKEYSIG更新出bug

问题描述1：

解决方法：

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 71A1D0EFCFEB6281FD0437C93D5919B448457EE0

再次更新：sudo apt-get update

问题描述2：

The following signatures were invalid: EXPKEYSIG F42ED6FBAB17C654 Open Robotics <info@osrfoundation.org>
The following signatures were invalid: EXPKEYSIG 3D5919B448457EE0 Bazel Developer (Bazel APT repository key) <bazel-dev@googlegroups.com>

解决方法：

apt list --upgradable
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys F42ED6FBAB17C654
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3D5919B448457EE0
apt update

问题描述3：

apt update
Hit:1 http://mirrors.aliyun.com/ubuntu bionic InRelease
Hit:2 http://mirrors.aliyun.com/ubuntu bionic-updates InRelease                                          
Hit:3 http://mirrors.aliyun.com/ubuntu bionic-security InRelease                                         
Get:4 https://storage.googleapis.com/bazel-apt stable InRelease [2,256 B]          
Err:4 https://storage.googleapis.com/bazel-apt stable InRelease 
  The following signatures were invalid: EXPKEYSIG 3D5919B448457EE0 Bazel Developer (Bazel APT repository key) <bazel-dev@googlegroups.com>
Fetched 2,256 B in 1s (2,204 B/s)
Reading package lists... Done
Building dependency tree       
Reading state information... Done
311 packages can be upgraded. Run 'apt list --upgradable' to see them.
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://storage.googleapis.com/bazel-apt stable InRelease: The following signatures were invalid: EXPKEYSIG 3D5919B448457EE0 Bazel Developer (Bazel APT repository key) <bazel-dev@googlegroups.com>
W: Failed to fetch https://storage.googleapis.com/bazel-apt/dists/stable/InRelease  The following signatures were invalid: EXPKEYSIG 3D5919B448457EE0 Bazel Developer (Bazel APT repository key) <bazel-dev@googlegroups.com>
W: Some index files failed to download. They have been ignored, or old ones used instead.

解决方法：

curl https://bazel.build/bazel-release.pub.gpg | sudo apt-key add -
# Followed by
sudo apt-get update

参考资料：

https://github.com/bazelbuild/bazel/issues/5261
https://blog.csdn.net/weixin_32820767_index=4
https://github.com/bazelbuild/bazel/issues/5261#issuecomment-392044252