Bump curb from 1.1.0 to 1.2.0

Bumps [curb](https://github.com/taf2/curb) from 1.1.0 to 1.2.0.
- [Changelog](https://github.com/taf2/curb/blob/master/ChangeLog.md)
- [Commits](https://github.com/taf2/curb/commits)

---
updated-dependencies:
- dependency-name: curb
  dependency-version: 1.2.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Gemfile

@@ -74,7 +74,7 @@ group :test do
 
     # Note: curb gem requires curl libraries
     # sudo apt-get install libcurl4-openssl-dev
-    gem 'curb', '~> 1.1'
+    gem 'curb', '~> 1.2'
 
     # Note: selenium-webdriver 3.x is incompatible with Firefox version 48 and prior
     # gem 'selenium' # Requires old version of selenium which is no longer available