Update pg 0.18.4 -> 1.0

What does this MR do?

Update pg gem

https://bitbucket.org/ged/ruby-pg/src/d8734ec382c9af8bd8bbe062d3668c93dd4ecf5b/History.rdoc?at=default&fileviewer=file-view-default

Deprecated:

• Deprecate Ruby older than 2.2.
• Deprecate Connection#socket in favor of #socket_io.

Removed:

• Remove compatibility code for Ruby < 2.0 and PostgreSQL < 9.2.
• Remove partial compatibility with Rubinius.
• Remove top-level constants PGconn, PGresult, and PGError.

== v0.19.0 [2016-09-21] Michael Granger ged@FaerieMUD.org

• Deprecate Ruby 1.9

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

Debian already has pg 0.19. But latest upstream is 1.0. So both can update to 1.0.

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• Internationalization required/considered
• End-to-end tests pass (package-qa manual pipeline job)

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