Align postgresql version used with gerrit core one

In this stable-2.16 version, the postgresql dependency is only used by
the side executor component of this plugin, beside tests. In core, the
plugin gets that dependency from gerrit (core).

Change-Id: I170c843652e7118e487100c5f67a740b513173ef
diff --git a/external_plugin_deps.bzl b/external_plugin_deps.bzl
index 363ebc3..0eedbad 100644
--- a/external_plugin_deps.bzl
+++ b/external_plugin_deps.bzl
@@ -74,8 +74,8 @@
 
     maven_jar(
         name = "postgresql",
-        artifact = "org.postgresql:postgresql:42.2.4",
-        sha1 = "dff98730c28a4b3a3263f0cf4abb9a3392f815a7",
+        artifact = "org.postgresql:postgresql:42.2.5",
+        sha1 = "951b7eda125f3137538a94e2cbdcf744088ad4c2",
     )
 
     maven_jar(