Bump pg from 0.21.0 to 1.2.3

Bumps [pg](https://github.com/ged/ruby-pg) from 0.21.0 to 1.2.3.
- [Release notes](https://github.com/ged/ruby-pg/releases)
- [Changelog](https://github.com/ged/ruby-pg/blob/master/History.rdoc)
- [Commits](ged/ruby-pg@v0.21.0...v1.2.3)

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

Gemfile

@@ -7,7 +7,7 @@ git_source(:github) do |repo_name|
 end
 
 gem 'rails', '~> 5.1.3'
-gem 'pg', '~> 0.18'
+gem 'pg', '~> 1.2'
 gem 'puma', '~> 3.7'
 gem 'sass-rails', '~> 5.0'
 gem 'uglifier', '>= 1.3.0'

Gemfile.lock

@@ -96,7 +96,7 @@ GEM
     nio4r (2.1.0)
     nokogiri (1.8.0)
       mini_portile2 (~> 2.2.0)
-    pg (0.21.0)
+    pg (1.2.3)
     puma (3.10.0)
     rack (2.0.3)
     rack-test (0.6.3)
@@ -226,7 +226,7 @@ DEPENDENCIES
   jbuilder (~> 2.5)
   jquery-rails
   listen (>= 3.0.5, < 3.2)
-  pg (~> 0.18)
+  pg (~> 1.2)
   puma (~> 3.7)
   rails (~> 5.1.3)
   rails_12factor