Merge pull request tumblr#571 from tumblr/felix/changelog

Update changelog for v2.2.0

Merge pull request tumblr#490 from tumblr/will-collins-2.1.0

Update changelog for 2.1.0 release

Adding changelog for 2.0.0 release (tumblr#467)

* Adding changelog for 2.0.0 release

* Make changelog markdown

Fix other reference to net-ssh 2.8.0

Merge pull request tumblr#129 from tumblr/will-replace-dash-in-shells…

…cript-variables

Ensure variable names are valid POSIX names when using text/x-shellscript API endpoint.

Cutting release 1.2.3

Version 1.2.2

Version 1.2.1