[release 2.1.x] Updated Mojave libpqxx dependency

[scottarnette]

Change Description

A recent base image update for MacOS 10.14 updated the libpqxx dependency acquired through Homebrew. This dependency, while seemingly acquires libpqxx 7.2.1, was actually downloading libpqxx 7.3.1 per Buildkite logs.

-- Checking for module 'libpqxx>=6.0'

--   Found libpqxx, version 7.3.1

This change updates the Homebrew formula we are using in the MacOS 10.14 pinned and unpinned builds. We usually don't pin specific versions in unpinned builds, but libpqxx 7.3.1 has been especially problematic on Mojave builds by trying to perform an include that doesn't exist in that SDK.

dyld: lazy symbol binding failed: Symbol not found: __ZNSt3__16__itoa8__u32toaEjPc
  Referenced from: /usr/local/opt/libpqxx/lib/libpqxx-7.3.dylib
  Expected in: /usr/lib/libc++.1.dylib
dyld: Symbol not found: __ZNSt3__16__itoa8__u32toaEjPc
  Referenced from: /usr/local/opt/libpqxx/lib/libpqxx-7.3.dylib
  Expected in: /usr/lib/libc++.1.dylib

See:
https://buildkite.com/EOSIO/eosio/builds/26982 | Passing Mac 10.14 pinned build.
https://buildkite.com/EOSIO/eosio-build-unpinned/builds/5592 | Passing Mac 10.14 unpinned build.

Change Type

Select ONE:

• Documentation

• Stability bug fix

• Other

• Other - special case

Testing Changes

Select ANY that apply:

• New Tests

• Existing Tests

• Test Framework

• CI System

• Other

Consensus Changes

• Consensus Changes

API Changes

• API Changes

Documentation Additions

• Documentation Additions

[kj4ezj]

🍺