Fixed message Regex (sds#767)

Author: bert-mccutchen

lib/overcommit/hook/pre_commit/stylelint.rb

@@ -8,7 +8,7 @@ class Stylelint < Base
     # example of output:
     # index.css: line 4, col 4, error - Expected indentation of 2 spaces (indentation)
 
-    MESSAGE_REGEX = /^(?<file>.+):\D*(?<line>\d+).*$/.freeze
+    MESSAGE_REGEX = /^(?<file>[^:]+):\D*(?<line>\d+).*$/.freeze
 
     def run
       result = execute(command, args: applicable_files)