Update middleman-hashicorp to 0.3.28 for mega nav fixes

Fixes detailed at https://github.com/hashicorp/middleman-hashicorp/pull/47

website/Gemfile

@@ -1,3 +1,3 @@
 source "https://rubygems.org"
 
-gem "middleman-hashicorp", "0.3.26"
+gem "middleman-hashicorp", "0.3.28"

website/Gemfile.lock

@@ -6,7 +6,7 @@ GEM
       minitest (~> 5.1)
       thread_safe (~> 0.3, >= 0.3.4)
       tzinfo (~> 1.1)
-    autoprefixer-rails (7.1.1)
+    autoprefixer-rails (7.1.1.2)
       execjs
     bootstrap-sass (3.3.7)
       autoprefixer-rails (>= 5.2.1)
@@ -78,7 +78,7 @@ GEM
       rack (>= 1.4.5, < 2.0)
       thor (>= 0.15.2, < 2.0)
       tilt (~> 1.4.1, < 2.0)
-    middleman-hashicorp (0.3.26)
+    middleman-hashicorp (0.3.28)
       bootstrap-sass (~> 3.3)
       builder (~> 3.2)
       middleman (~> 3.4)
@@ -118,10 +118,10 @@ GEM
     rack-test (0.6.3)
       rack (>= 1.0)
     rb-fsevent (0.9.8)
-    rb-inotify (0.9.8)
-      ffi (>= 0.5.0)
+    rb-inotify (0.9.10)
+      ffi (>= 0.5.0, < 2)
     redcarpet (3.4.0)
-    rouge (2.0.7)
+    rouge (2.1.1)
     sass (3.4.24)
     sprockets (2.12.4)
       hike (~> 1.2)
@@ -153,7 +153,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
-  middleman-hashicorp (= 0.3.26)
+  middleman-hashicorp (= 0.3.28)
 
 BUNDLED WITH
-   1.14.6
+   1.15.1

website/Makefile

@@ -1,4 +1,4 @@
-VERSION?="0.3.26"
+VERSION?="0.3.28"
 
 build:
 	@echo "==> Starting build in Docker..."

website/packer.json

@@ -8,7 +8,7 @@
   "builders": [
     {
       "type": "docker",
-      "image": "hashicorp/middleman-hashicorp:0.3.26",
+      "image": "hashicorp/middleman-hashicorp:0.3.28",
       "discard": "true",
       "run_command": ["-d", "-i", "-t", "{{ .Image }}", "/bin/sh"]
     }