(maint) Update CLI version on PRs

This updates the Chocolatey CLI version used when
building/running on pull requests to the version that
we document as the minimum supported version in
this repository.

.appveyor.yml

@@ -45,7 +45,7 @@ environment:
 
   #Chocolatey version we want to use when checking for updates (usually latest).
   choco_version: '2.4.0'
-  choco_version_pr: '2.0.0' # Should be kept to the version available one year ago
+  choco_version_pr: '2.2.2' # Should be kept at the minimum version supported that is listed on <https://github.com/chocolatey-community/chocolatey-packages/wiki/Supported-Chocolatey-CLI-versions>
   nupkg_cache_path: C:\packages
 
 init: