chore(deps): update dependency pg to v1.6.2 (#271)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

pact_broker/Gemfile.lock

@@ -108,7 +108,7 @@ GEM
       thor (~> 1.0)
     padrino-support (0.16.0.pre3)
     parslet (2.0.0)
-    pg (1.5.9)
+    pg (1.6.2)
     psych (5.2.6)
       date
       stringio