Update sqlite3 requirement from ~> 1.3.6 to ~> 1.4.0

Updates the requirements on [sqlite3](https://github.com/sparklemotion/sqlite3-ruby) to permit the latest version.
- [Release notes](https://github.com/sparklemotion/sqlite3-ruby/releases)
- [Changelog](https://github.com/sparklemotion/sqlite3-ruby/blob/master/CHANGELOG.rdoc)
- [Commits](sparklemotion/sqlite3-ruby@v1.3.6...v1.4.0)

Signed-off-by: dependabot[bot] <support@dependabot.com>

calagator.gemspec

@@ -63,7 +63,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency "rspec-rails", "~> 3.2"
   s.add_development_dependency "selenium-webdriver"
   s.add_development_dependency "simplecov", "~> 0.10.0"
-  s.add_development_dependency "sqlite3", "~> 1.3.6"
+  s.add_development_dependency "sqlite3", "~> 1.4.0"
   s.add_development_dependency "sunspot_solr",  "~> 2.1"
   s.add_development_dependency "timecop", "~> 0.7.1"
   s.add_development_dependency "webmock", "~> 3.5"