Bump pg from 0.20.0 to 1.1.3

Bumps [pg](https://bitbucket.org/ged/ruby-pg) from 0.20.0 to 1.1.3.
- [Changelog](https://bitbucket.org/ged/ruby-pg/src/master/History.rdoc)
- [Commits](https://bitbucket.org/ged/ruby-pg/branches/compare/v1.1.3..v0.20.0)

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

Author: dependabot-support

Gemfile.lock

@@ -146,7 +146,7 @@ GEM
     nokogiri (1.8.5)
       mini_portile2 (~> 2.3.0)
     normalize-rails (3.0.3)
-    pg (0.20.0)
+    pg (1.1.3)
     pry (0.10.4)
       coderay (~> 1.1.0)
       method_source (~> 0.8.1)