Update gems (#1637)

Gemfile

@@ -6,5 +6,5 @@ end
 
 gemspec
 
-gem "rake", '~> 12.3', '>= 12.3.3'
+gem "rake", '~> 13.0'
 

gollum.gemspec

@@ -23,18 +23,18 @@ Gem::Specification.new do |s|
   s.rdoc_options = ['--charset=UTF-8']
   s.extra_rdoc_files = %w[README.md LICENSE]
 
-  s.add_dependency 'gollum-lib', '~> 5.0'
+  s.add_dependency 'gollum-lib', '~> 5.1'
   s.add_dependency 'kramdown', '~> 2.3'
   s.add_dependency 'kramdown-parser-gfm', '~> 1.1.0'
   s.add_dependency 'sinatra', '~> 2.0'
   s.add_dependency 'sinatra-contrib', '~> 2.0'
-  s.add_dependency 'mustache', ['>= 0.99.5', '< 1.0.0']
+  s.add_dependency 'mustache-sinatra', '~> 1.0'
   s.add_dependency 'useragent', '~> 0.16.2'
   s.add_dependency 'gemojione', '~> 4.1'
-  s.add_dependency 'octicons', '~> 8.5'
+  s.add_dependency 'octicons', '~> 12.0'
   s.add_dependency 'sprockets', '~> 3.7'
   s.add_dependency 'sass', '~> 3.5'
-  s.add_dependency 'uglifier', '~> 3.2'
+  s.add_dependency 'uglifier', '~> 4.2'
   s.add_dependency 'sprockets-helpers', '~> 1.2'
   s.add_dependency 'rss', '~> 0.2.9'
   s.add_dependency 'therubyrhino', '~> 2.1.0'

lib/gollum/templates/overview.mustache

@@ -18,7 +18,7 @@
 						<span class="pr-2">{{{icon}}}</span>
 						<span><a href="{{url}}">{{name}}</a></span>
 						{{#allow_editing}}
-							{{#is_file}}<button class="btn btn-sm float-right delete-file" data-file-path="{{file_path}}" data-confirm="Are you sure you want to delete {{name}}?">{{#octicon}}trashcan{{/octicon}}</button>{{/is_file}}
+							{{#is_file}}<button class="btn btn-sm float-right delete-file" data-file-path="{{file_path}}" data-confirm="Are you sure you want to delete {{name}}?">{{#octicon}}trash{{/octicon}}</button>{{/is_file}}
 						{{/allow_editing}}
 		      </li>
 				{{/files_folders}}