feat(deps): upgrade pg-sql2 and postgraphile-core

[benjie]

• Better TypeScript support
• Many fixes, including:
  • enable update/delete mutations for tables lacking primary keys
  • fix bug in introspection query that could in some very rare circumstances cause tables or functions to be omitted from the generated schema
  • fixing a template string that accidentally had straight quotes (thanks @mathroc)
  • more useful error message when using legacy graphql versions with graphile-utils
  • fix bug in regex for validating long aliases
• More information in some places for plugins to use
• Better errors in a few places
• hstore support
• inet support thanks to @syndesis
• graphile-utils enhancements
  • including enum support thanks to @bradleyayers