content_type_whitelist on 0.11.x

[tneems]

I saw that with the release of 0.11.1 there was a backport for ImageTragick suggesting that content_type_whitelist be used to mitigate the vulnerability, but unless I'm losing it I don't believe there is support in 0.11.1 for content_type_whitelist, it's only on master.

[locriani]

That's correct, it was an oversight on my part. There's a PR currently against the 0.11-stable branch that backports the content_type_whitelist that you can use in the interim: #1937

[thiagofm]

@tneems I've generated a release for 0.11.2, please update :)