Bump middleman from 4.2.1 to 4.3.7

Bumps [middleman](https://github.com/middleman/middleman) from 4.2.1 to 4.3.7.
- [Release notes](https://github.com/middleman/middleman/releases)
- [Changelog](https://github.com/middleman/middleman/blob/v4.3.7/CHANGELOG.md)
- [Commits](middleman/middleman@v4.2.1...v4.3.7)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Gemfile

@@ -1,7 +1,7 @@
 source 'https://rubygems.org'
 
 gem 'kramdown', '~> 1.17'
-gem 'middleman', '~> 4.2'
+gem 'middleman', '~> 4.3'
 gem 'middleman-deploy', '~> 2.0.0.pre.alpha'
 gem 'middleman-autoprefixer', '~> 2.10'
 gem 'middleman-livereload', '~> 3.4'

Gemfile.lock

@@ -1,70 +1,67 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    activesupport (5.0.7.1)
+    activesupport (5.2.4.3)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 0.7, < 2)
       minitest (~> 5.1)
       tzinfo (~> 1.1)
-    addressable (2.6.0)
-      public_suffix (>= 2.0.2, < 4.0)
+    addressable (2.7.0)
+      public_suffix (>= 2.0.2, < 5.0)
     ast (2.4.1)
     autoprefixer-rails (9.4.10.2)
       execjs
-    backports (3.12.0)
+    backports (3.18.1)
     coffee-script (2.4.1)
       coffee-script-source
       execjs
     coffee-script-source (1.12.2)
-    compass-import-once (1.0.5)
-      sass (>= 3.2, < 3.5)
-    concurrent-ruby (1.1.4)
+    concurrent-ruby (1.1.6)
     contracts (0.13.0)
     diff-lcs (1.3)
-    dotenv (2.7.1)
+    dotenv (2.7.6)
     em-websocket (0.5.1)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0.6.0)
     erubis (2.7.0)
     eventmachine (1.2.7)
     execjs (2.7.0)
     fast_blank (1.0.0)
-    fastimage (2.1.5)
-    ffi (1.10.0)
+    fastimage (2.1.7)
+    ffi (1.13.1)
     fuubar (2.5.0)
       rspec-core (~> 3.0)
       ruby-progressbar (~> 1.4)
-    haml (5.0.4)
+    haml (5.1.2)
       temple (>= 0.8.0)
       tilt
     hamster (3.0.0)
       concurrent-ruby (~> 1.0)
     hashie (3.6.0)
     http_parser.rb (0.6.0)
-    i18n (0.7.0)
+    i18n (0.9.5)
+      concurrent-ruby (~> 1.0)
     kramdown (1.17.0)
     listen (3.0.8)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
-    memoist (0.16.0)
-    middleman (4.2.1)
+    memoist (0.16.2)
+    middleman (4.3.7)
       coffee-script (~> 2.2)
-      compass-import-once (= 1.0.5)
       haml (>= 4.0.5)
       kramdown (~> 1.2)
-      middleman-cli (= 4.2.1)
-      middleman-core (= 4.2.1)
-      sass (>= 3.4.0, < 4.0)
+      middleman-cli (= 4.3.7)
+      middleman-core (= 4.3.7)
     middleman-autoprefixer (2.10.1)
       autoprefixer-rails (~> 9.1)
       middleman-core (>= 3.3.3)
-    middleman-cli (4.2.1)
+    middleman-cli (4.3.7)
       thor (>= 0.17.0, < 2.0)
-    middleman-core (4.2.1)
-      activesupport (>= 4.2, < 5.1)
+    middleman-core (4.3.7)
+      activesupport (>= 4.2, < 6.0)
       addressable (~> 2.3)
       backports (~> 3.6)
-      bundler (~> 1.1)
+      bundler
       contracts (~> 0.13.0)
       dotenv
       erubis
@@ -73,15 +70,15 @@ GEM
       fastimage (~> 2.0)
       hamster (~> 3.0)
       hashie (~> 3.4)
-      i18n (~> 0.7.0)
+      i18n (~> 0.9.0)
       listen (~> 3.0.0)
       memoist (~> 0.14)
       padrino-helpers (~> 0.13.0)
       parallel
       rack (>= 1.4.5, < 3)
-      sass (>= 3.4)
+      sassc (~> 2.0)
       servolux
-      tilt (~> 2.0)
+      tilt (~> 2.0.9)
       uglifier (~> 3.0)
     middleman-deploy (2.0.0.pre.alpha)
       middleman-core (>= 3.2)
@@ -91,7 +88,7 @@ GEM
       em-websocket (~> 0.5.1)
       middleman-core (>= 3.3)
       rack-livereload (~> 0.3.15)
-    minitest (5.11.3)
+    minitest (5.14.1)
     net-sftp (2.1.2)
       net-ssh (>= 2.6.5)
     net-ssh (5.0.2)
@@ -105,14 +102,14 @@ GEM
     parser (2.7.1.4)
       ast (~> 2.4.1)
     ptools (1.3.5)
-    public_suffix (3.0.3)
+    public_suffix (4.0.5)
     rack (2.2.3)
     rack-livereload (0.3.17)
       rack
     rainbow (3.0.0)
     rake (13.0.1)
-    rb-fsevent (0.10.3)
-    rb-inotify (0.10.0)
+    rb-fsevent (0.10.4)
+    rb-inotify (0.10.1)
       ffi (~> 1.0)
     regexp_parser (1.7.1)
     rexml (3.2.4)
@@ -141,13 +138,14 @@ GEM
     rubocop-ast (0.1.0)
       parser (>= 2.7.0.1)
     ruby-progressbar (1.10.1)
-    sass (3.4.25)
+    sassc (2.4.0)
+      ffi (~> 1.9)
     servolux (0.13.0)
-    temple (0.8.0)
-    thor (0.20.0)
+    temple (0.8.2)
+    thor (1.0.1)
     thread_safe (0.3.6)
-    tilt (2.0.9)
-    tzinfo (1.2.5)
+    tilt (2.0.10)
+    tzinfo (1.2.7)
       thread_safe (~> 0.1)
     uglifier (3.2.0)
       execjs (>= 0.3.0, < 3)
@@ -159,7 +157,7 @@ PLATFORMS
 DEPENDENCIES
   fuubar
   kramdown (~> 1.17)
-  middleman (~> 4.2)
+  middleman (~> 4.3)
   middleman-autoprefixer (~> 2.10)
   middleman-deploy (~> 2.0.0.pre.alpha)
   middleman-livereload (~> 3.4)