Bump pg from 1.4.6 to 1.5.3

Bumps [pg](https://github.com/ged/ruby-pg) from 1.4.6 to 1.5.3.
- [Release notes](https://github.com/ged/ruby-pg/releases)
- [Changelog](https://github.com/ged/ruby-pg/blob/master/History.md)
- [Commits](https://github.com/ged/ruby-pg/compare/v1.4.6...v1.5.3)

---
updated-dependencies:
- dependency-name: pg
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Gemfile

@@ -115,7 +115,7 @@ group :production do
 end
 
 group :test, :production do
-  gem 'pg', '~> 1.4'
+  gem 'pg', '~> 1.5'
 
   gem "mini_racer", "~> 0.6.3" # TODO: audit whether we can remove this
 end

Gemfile.lock

@@ -1502,7 +1502,7 @@ GEM
       faraday (~> 1.4)
       faraday_middleware (~> 1)
     paypalhttp (1.0.1)
-    pg (1.4.6)
+    pg (1.5.3)
     pkg-config (1.5.1)
     pry (0.14.2)
       coderay (~> 1.1)
@@ -1731,7 +1731,7 @@ DEPENDENCIES
   paranoia
   paypal-checkout-sdk
   paypal_client
-  pg (~> 1.4)
+  pg (~> 1.5)
   pry
   puma (~> 5.6)
   puma-heroku