Do not lock rails-i18n in Gemfile

There is not reason to not use new versions of rails-i18n. Update to
last version 1.6.0.

Gemfile

@@ -32,7 +32,7 @@ gem 'carrierwave-bombshelter'
 gem 'mini_magick'
 
 # for internationalizing
-gem 'rails-i18n', '~> 5.0.0'
+gem 'rails-i18n'
 
 # as authentification framework
 gem 'devise'

Gemfile.lock

@@ -235,7 +235,7 @@ GEM
     htmlentities (4.3.4)
     http-cookie (1.0.3)
       domain_name (~> 0.5)
-    i18n (0.9.5)
+    i18n (1.6.0)
       concurrent-ruby (~> 1.0)
     i18n_data (0.8.0)
     inversion (1.1.1)
@@ -422,9 +422,9 @@ GEM
       nokogiri (>= 1.6)
     rails-html-sanitizer (1.0.4)
       loofah (~> 2.2, >= 2.2.2)
-    rails-i18n (5.0.4)
-      i18n (~> 0.7)
-      railties (~> 5.0)
+    rails-i18n (5.1.3)
+      i18n (>= 0.7, < 2)
+      railties (>= 5.0, < 6)
     railties (5.0.7.2)
       actionpack (= 5.0.7.2)
       activesupport (= 5.0.7.2)
@@ -685,7 +685,7 @@ DEPENDENCIES
   rails-assets-trianglify!
   rails-assets-waypoints!
   rails-controller-testing
-  rails-i18n (~> 5.0.0)
+  rails-i18n
   rdoc-generator-fivefish
   recaptcha
   redcarpet
@@ -722,4 +722,4 @@ RUBY VERSION
    ruby 2.5.0p0
 
 BUNDLED WITH
-   1.17.1
+   1.17.3