There's a closed pull request on the void-packages repository

New package: postgresql-plr-8.4.6
https://github.com/void-linux/void-packages/pull/49969

Description:
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NOTE: I am **not** willing to maintain this package as I am not familiar with R nor postgresql. Anyone is free to take over this package.

This PR will likely stay in draft mode for the time being.

#### Testing the changes
- I tested the changes in this PR: **NO** (but orca8 said on IRC that it works for them)

#### New package
- This new package conforms to the [package requirements](https://github.com/void-linux/void-packages/blob/master/CONTRIBUTING.md#package-requirements): **YES**

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