Bump pg from 1.3.0 to 1.3.1

Bumps pg from 1.3.0 to 1.3.1.

Changelog

Sourced from pg's changelog.

== v1.3.1 [YYYY-MM-DD] Michael Granger ged@FaerieMUD.org

Bugfixes:

• Fix wrong handling of socket writability on Windows introduced in #417. This caused starvation in conn.put_copy_data.
• Fix error in PG.version_string(true). #419
• Fix a regression in pg 1.3.0 where Ruby 2.x busy-looping any fractional seconds for every wait. #420

Enhancements:

• Raise an error when conn.copy_data is used in nonblocking mode.

Commits

• 6c436bd Update History.rdoc for #420
• 300e94e Merge pull request #420 from ennova/ruby-2-wait-cpu
• 20bab5e Fix high CPU usage when waiting with a timeout on Ruby < 3.0
• 28a3bf7 Prepare History.rdoc for pg-1.3.1
• 7844548 Fix error PG.version_string(true)
• 0232b28 Retry occasional failing test
• 8a25ca4 Fix wrong handling of socket writability on Windows
• 22e91a3 Add a new test for COPY'ing lots of data to the server
• 84aca71 Bump VERSION to 1.3.1
• 8e8dd31 Raise an error when #copy_data is used in nonblocking mode
• Additional commits viewable in compare view