Upgrade charlock_holmes to version 0.7.6 (#6966)

This version fixes compilation errors when trying to build its native extension with ICU 61.

Gemfile

@@ -25,7 +25,7 @@ gem 'active_model_serializers', '~> 0.10'
 gem 'addressable', '~> 2.5'
 gem 'bootsnap'
 gem 'browser'
-gem 'charlock_holmes', '~> 0.7.5'
+gem 'charlock_holmes', '~> 0.7.6'
 gem 'iso-639'
 gem 'chewy', '~> 5.0'
 gem 'cld3', '~> 3.2.0'

Gemfile.lock

@@ -113,7 +113,7 @@ GEM
       xpath (~> 2.0)
     case_transform (0.2)
       activesupport
-    charlock_holmes (0.7.5)
+    charlock_holmes (0.7.6)
     chewy (5.0.0)
       activesupport (>= 4.0)
       elasticsearch (>= 2.0.0)
@@ -632,7 +632,7 @@ DEPENDENCIES
   capistrano-rbenv (~> 2.1)
   capistrano-yarn (~> 2.0)
   capybara (~> 2.15)
-  charlock_holmes (~> 0.7.5)
+  charlock_holmes (~> 0.7.6)
   chewy (~> 5.0)
   cld3 (~> 3.2.0)
   climate_control (~> 0.2)