Dependency updates and lint (#530)

* update sqlite3, ruby min version

* fix rubocop linting warnings

* make linting simpler by including .editorconfig

* Revert sqlite3 to a version that works

Author: antpaw

.editorconfig

@@ -0,0 +1,13 @@
+# editorconfig.org
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.md]
+trim_trailing_whitespace = false

test/gemfiles/5.1.gemfile

@@ -12,6 +12,6 @@ group :test do
   gem "diffy"
   gem "equivalent-xml"
   gem "mocha"
-  gem "sqlite3", "~> 1.3.6"
+  gem "sqlite3", "~> 1.4"
   gem "timecop", "~> 0.7.1"
 end

test/gemfiles/5.2.gemfile

@@ -12,6 +12,6 @@ group :test do
   gem "diffy"
   gem "equivalent-xml"
   gem "mocha"
-  gem "sqlite3", "~> 1.3.6"
+  gem "sqlite3", "~> 1.4"
   gem "timecop", "~> 0.7.1"
 end