Revert "Bump nokogiri from 1.12.5 to 1.13.10 (sass#699)" (sass#705)

This reverts commit 024ff9e.

Gemfile

@@ -10,7 +10,7 @@ gem "middleman-livereload",   "~> 3.4.5"
 gem "middleman-minify-html",  "~> 3.4.1"
 gem "middleman-syntax",       "~> 2.0.0"
 gem "modular-scale",          "~> 2.1.1"
-gem "nokogiri",               "~> 1.13"
+gem "nokogiri",               "~> 1.12"
 gem "puma"
 gem "rack"
 gem "rack-contrib"

Gemfile.lock

@@ -115,14 +115,14 @@ GEM
     mime-types (3.2.2)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2018.0812)
-    mini_portile2 (2.8.1)
+    mini_portile2 (2.6.1)
     minitest (5.11.3)
     modular-scale (2.1.1)
       compass (>= 0.12.0)
     multi_json (1.13.1)
     nio4r (2.5.8)
-    nokogiri (1.13.10)
-      mini_portile2 (~> 2.8.0)
+    nokogiri (1.12.5)
+      mini_portile2 (~> 2.6.1)
       racc (~> 1.4)
     padrino-helpers (0.12.9)
       i18n (~> 0.6, >= 0.6.7)
@@ -133,7 +133,7 @@ GEM
     parallel (1.18.0)
     puma (5.6.4)
       nio4r (~> 2.0)
-    racc (1.6.2)
+    racc (1.5.2)
     rack (1.6.12)
     rack-conditional (0.3.1)
       rack (>= 1.6.11)
@@ -201,7 +201,7 @@ DEPENDENCIES
   middleman-minify-html (~> 3.4.1)
   middleman-syntax (~> 2.0.0)
   modular-scale (~> 2.1.1)
-  nokogiri (~> 1.13)
+  nokogiri (~> 1.12)
   puma
   rack
   rack-conditional (~> 0.3)