Error: root version is N, but should be: N+1

[lucklove]

Bug Report

After #967, we support rotate the root.json.

However, the TiUP (version < v1.3.0) can't get new root.json correctly because the early implementation has a bug introduced by #230 (the very beginning commit for TiUP TUF implemmentation).

This bug has been fixed in #967, and planed to be released in v1.3.0.

The old TiUP will not work after we rotate root.json online (https://tiup-mirrors.pingcap.com), this issue is used to record this problem in case someone get into trouble unfortunately.

If you are troubled by this bug, just reinstall the tiup client by:

curl --proto '=https' --tlsv1.2 -sSf https://tiup-mirrors.pingcap.com/install.sh | sh 

And update your installed components incase some of them (eg. tiup-cluster) reference to the old code:

tiup update --all