Update dependency mocha to v2.6.0

Author: renovate[bot]

Gemfile

@@ -30,7 +30,7 @@ gem 'haml', '5.2.2'
 gem 'jira-ruby', '2.3.0'
 gem 'mail', '2.8.1'
 gem 'matrix', '0.4.2'
-gem 'mocha', '2.5.0', require: false
+gem 'mocha', '2.6.0', require: false
 gem 'net-smtp', '0.5.0'
 gem 'nokogiri', '1.16.7'
 gem 'octokit', '9.2.0'

Gemfile.lock

@@ -92,7 +92,7 @@ GEM
     mini_mime (1.1.5)
     mini_portile2 (2.8.7)
     minitest (5.22.2)
-    mocha (2.5.0)
+    mocha (2.6.0)
       ruby2_keywords (>= 0.0.5)
     multi_json (1.15.0)
     multi_xml (0.7.1)
@@ -250,7 +250,7 @@ DEPENDENCIES
   jira-ruby (= 2.3.0)
   mail (= 2.8.1)
   matrix (= 0.4.2)
-  mocha (= 2.5.0)
+  mocha (= 2.6.0)
   net-smtp (= 0.5.0)
   nokogiri (= 1.16.7)
   octokit (= 9.2.0)