Update postgresql 42.2.25 to 42.2.26

[rc-mattschwager]

Hi there, I'm hoping to bump postgresql to 42.2.26 to mitigate new security vulnerabilities.

Building on: https://github.com/jruby/activerecord-jdbc-adapter/pull/1102

Downloads here: https://jdbc.postgresql.org/download/

Hashes as follows:

$ sha256sum postgresql-42.2.26.jar 
98827b8e2b43a0ae603b52b3ec9e3cb5031e0afdc6401f868b6daee658712443  postgresql-42.2.26.jar
$ sha256sum postgresql-42.2.26.jre6.jar 
663161c39abbec8fe0e673a2577935baddb205bd571cf610accdf6939c45f5fa  postgresql-42.2.26.jre6.jar
$ sha256sum postgresql-42.2.26.jre7.jar 
d0c04d1cdd49b44397376bd3026b64a604fa041a6fba059d77a535458e2baa2d  postgresql-42.2.26.jre7.jar

[rc-mattschwager]

Hey @kares, any chance you could give this a quick review?

[kares]

Closing as duplicate, was merged at https://github.com/jruby/activerecord-jdbc-adapter/issues/1131