Upgraded bootstrap to 4.3.1 to apply security fix

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

Gemfile

@@ -7,7 +7,7 @@ gem 'html-proofer', group: :development
 gem 'jekyll', '~> 3.8.4'
 group :jekyll_plugins do
   gem 'autoprefixer-rails'
-  gem 'bootstrap', '~> 4.1.2'
+  gem 'bootstrap', '~> 4.3.1'
   gem 'jekyll-assets', '~> 3.0.9'
   gem 'jekyll-avatar'
   gem 'jekyll-coffeescript'

Gemfile.lock

@@ -1,6 +1,19 @@
 GEM
   remote: https://rubygems.org/
   specs:
+    actionpack (5.2.1)
+      actionview (= 5.2.1)
+      activesupport (= 5.2.1)
+      rack (~> 2.0)
+      rack-test (>= 0.6.3)
+      rails-dom-testing (~> 2.0)
+      rails-html-sanitizer (~> 1.0, >= 1.0.2)
+    actionview (5.2.1)
+      activesupport (= 5.2.1)
+      builder (~> 3.1)
+      erubi (~> 1.4)
+      rails-dom-testing (~> 2.0)
+      rails-html-sanitizer (~> 1.0, >= 1.0.3)
     activesupport (5.2.1)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 0.7, < 2)
@@ -11,10 +24,11 @@ GEM
     ast (2.4.0)
     autoprefixer-rails (9.3.1)
       execjs
-    bootstrap (4.1.3)
-      autoprefixer-rails (>= 6.0.3)
-      popper_js (>= 1.12.9, < 2)
-      sass (>= 3.5.2)
+    bootstrap (4.3.1)
+      autoprefixer-rails (>= 9.1.0)
+      popper_js (>= 1.14.3, < 2)
+      sassc-rails (>= 2.0.0)
+    builder (3.2.3)
     coffee-script (2.4.1)
       coffee-script-source
       execjs
@@ -24,9 +38,11 @@ GEM
     commonmarker (0.17.13)
       ruby-enum (~> 0.5)
     concurrent-ruby (1.1.3)
+    crass (1.0.4)
     em-websocket (0.5.1)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0.6.0)
+    erubi (1.8.0)
     ethon (0.11.0)
       ffi (>= 1.3.0)
     eventmachine (1.2.7)
@@ -178,7 +194,11 @@ GEM
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
       ruby_dep (~> 1.2)
+    loofah (2.2.3)
+      crass (~> 1.0.2)
+      nokogiri (>= 1.5.9)
     mercenary (0.3.6)
+    method_source (0.9.2)
     mini_portile2 (2.3.0)
     mini_racer (0.2.4)
       libv8 (>= 6.3)
@@ -201,7 +221,21 @@ GEM
     powerpack (0.1.2)
     public_suffix (3.0.3)
     rack (2.0.6)
+    rack-test (1.1.0)
+      rack (>= 1.0, < 3)
+    rails-dom-testing (2.0.3)
+      activesupport (>= 4.2.0)
+      nokogiri (>= 1.6)
+    rails-html-sanitizer (1.0.4)
+      loofah (~> 2.2, >= 2.2.2)
+    railties (5.2.1)
+      actionpack (= 5.2.1)
+      activesupport (= 5.2.1)
+      method_source
+      rake (>= 0.8.7)
+      thor (>= 0.19.0, < 2.0)
     rainbow (3.0.0)
+    rake (12.3.2)
     rb-fsevent (0.10.3)
     rb-inotify (0.9.10)
       ffi (>= 0.5.0, < 2)
@@ -225,15 +259,30 @@ GEM
     sass-listen (4.0.0)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
+    sassc (2.0.1)
+      ffi (~> 1.9)
+      rake
+    sassc-rails (2.1.0)
+      railties (>= 4.0.0)
+      sassc (>= 2.0)
+      sprockets (> 3.0)
+      sprockets-rails
+      tilt
     sawyer (0.8.1)
       addressable (>= 2.3.5, < 2.6)
       faraday (~> 0.8, < 1.0)
     sprockets (3.7.2)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
+    sprockets-rails (3.2.1)
+      actionpack (>= 4.0)
+      activesupport (>= 4.0)
+      sprockets (>= 3.0.0)
     terminal-table (1.8.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
+    thor (0.20.3)
     thread_safe (0.3.6)
+    tilt (2.0.9)
     typhoeus (1.3.1)
       ethon (>= 0.9.0)
     tzinfo (1.2.5)
@@ -249,7 +298,7 @@ PLATFORMS
 DEPENDENCIES
   activesupport
   autoprefixer-rails
-  bootstrap (~> 4.1.2)
+  bootstrap (~> 4.3.1)
   html-proofer
   jekyll (~> 3.8.4)
   jekyll-assets (~> 3.0.9)