Simplify the repo.

This also adjust the license to ISC.

.travis.yml

@@ -20,7 +20,8 @@ env:
     "
   matrix:
     - JEKYLL_BRANCH="master"
-    - JEKYLL_VERSION="~> 3.7.0"
+    - JEKYLL_VERSION="~> 3.8.0"
+    - JEKYLL_VERSION="~> 4.0.0"
     - LINTING=true
 rvm:
   - 2.6

COPYING

@@ -0,0 +1,14 @@
+Copyright 2012 - 2015 Aleksey V Zapparov
+Copyright 2015 - 2018 Jordon Bedwell
+
+Permission to use, copy, modify, and/or distribute this software for
+any purpose with or without fee is hereby granted, provided that the
+above copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
+AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
+OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

Gemfile

@@ -1,13 +1,14 @@
 # Frozen-string-literal: true
-# Copyright: 2012 - 2018 - MIT License
+# Copyright: 2012 - 2020 - MIT License
+# rubocop:disable Bundler/DuplicatedGem
 # Encoding: utf-8
 
 source "https://rubygems.org"
 gemspec
 
-sv = "~> 4.0.beta"
-gem "sprockets", ENV["SPROCKETS_VERSION"] || sv, require: false
-# rubocop:disable Bundler/DuplicatedGem
+s_version = "~> 4.0"
+j_version = "~> 4.0"
+gem "sprockets", ENV["SPROCKETS_VERSION"] || s_version, require: false
 if ENV["JEKYLL_VERSION"]
   gem "jekyll", ENV["JEKYLL_VERSION"], {
     require: false,
@@ -17,4 +18,6 @@ elsif ENV["JEKYLL_BRANCH"]
     git: "https://github.com/jekyll/jekyll",
     branch: ENV["JEKYLL_BRANCH"],
   }
+else
+  gem "jekyll", j_version
 end