Add a variable to define PostgreSQL version

[jpmjpmjpm]

This is more a question than an issue

Currently, the installed PostgreSQL version is not determined explicitly with a variable. Shouldn't a variable added? I ask the question as I have an app version installed early 2020 with PostgreSQL v12. However, I provisioned another server in October and I saw that PostgreSQL installed version is v13 while I was willing to have the same installation.

I can obviously modify my forked version but I was willing to have your views guys on the topic.

Thanks, Jean-Pierre.

[YPCrumble]

@jpmjpmjpm this is a really great suggestion.

I actually have a server that has two versions of Postgres installed simultaneously due to this issue...and I'm hesitant to try uninstalling the updated version for fear of breaking things. A PR would be awesome!

[jpmjpmjpm]

I created PR #169 to solve the issue. Thanks for reviewing it!

Note: by the way PR #156 is still waiting for a merge.