Minor bug-fix update

Everything you need to know about installation and update is in the v1.9.0 release notes.

v1.9.1 fixes a couple of problems that hopefully have affected just a few people. If you haven't had a problem, you probably don't need it, but it won't do any harm either.

1. Upgrades from versions before v1.8.0 resulted in a panic on running most commands due to a difference between pre-v1.8.0 ~/.ddev/global_config.yaml and v1.9.0.
2. Windows users who one way or another introduced CRs into their config.yaml saw failures due to over-aggressive validation by the golang yaml parser.

Commits since v1.9.0

4a94ab7 Revert to yaml.v2 since yaml.v3 doesn't work with CRLF (#1677)
30f68d8 Fix crash encountered with old global_config.yaml (#1673)