Removed jekyll assets

Signed-off-by: Jim Martens <github@2martens.de>

Gemfile

@@ -8,7 +8,6 @@ gem 'jekyll', '~> 3.8.4'
 group :jekyll_plugins do
   gem 'autoprefixer-rails'
   gem 'bootstrap', '~> 4.3.1'
-  gem 'jekyll-assets', '~> 3.0.12'
   gem 'jekyll-avatar'
   gem 'jekyll-coffeescript'
   gem 'jekyll-commonmark-ghpages'

Gemfile.lock

@@ -47,11 +47,8 @@ GEM
       ffi (>= 1.3.0)
     eventmachine (1.2.7)
     execjs (2.7.0)
-    extras (0.3.0)
-      forwardable-extended (~> 2.5)
     faraday (0.15.4)
       multipart-post (>= 1.2, < 3)
-    fastimage (2.1.5)
     ffi (1.10.0)
     forwardable-extended (2.6.0)
     gemoji (3.0.0)
@@ -84,17 +81,6 @@ GEM
       pathutil (~> 0.9)
       rouge (>= 1.7, < 4)
       safe_yaml (~> 1.0)
-    jekyll-assets (3.0.12)
-      activesupport (~> 5.0)
-      execjs (~> 2.7)
-      extras (~> 0.2)
-      fastimage (~> 2.0, >= 1.8)
-      jekyll (>= 3.5, < 4.0)
-      jekyll-sanity (~> 1.2)
-      liquid-tag-parser (~> 1.0)
-      nokogiri (~> 1.8)
-      pathutil (~> 0.16)
-      sprockets (>= 3.3, < 4.1.beta)
     jekyll-avatar (0.6.0)
       jekyll (~> 3.0)
     jekyll-coffeescript (1.1.1)
@@ -128,8 +114,6 @@ GEM
     jekyll-remote-theme (0.3.1)
       jekyll (~> 3.5)
       rubyzip (>= 1.2.1, < 3.0)
-    jekyll-sanity (1.2.0)
-      jekyll (~> 3.1)
     jekyll-sass-converter (1.5.2)
       sass (~> 3.4)
     jekyll-seo-tag (2.5.0)
@@ -188,9 +172,6 @@ GEM
     kramdown (1.17.0)
     libv8 (6.7.288.46.1)
     liquid (4.0.1)
-    liquid-tag-parser (1.9.0)
-      extras (~> 0.3)
-      liquid (>= 3.0, < 5.0)
     listen (3.1.5)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
@@ -304,7 +285,6 @@ DEPENDENCIES
   bootstrap (~> 4.3.1)
   html-proofer
   jekyll (~> 3.8.4)
-  jekyll-assets (~> 3.0.12)
   jekyll-avatar
   jekyll-coffeescript
   jekyll-commonmark-ghpages