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

i2pd: add -devel subpackage
https://github.com/void-linux/void-packages/pull/42915

Description:
#### Testing the changes
- I tested the changes in this PR: **YES**

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

#### Local build testing
- I built this PR locally for my native architecture, x86_64-musl
- I built this PR locally for these architectures (if supported. mark crossbuilds):
  - x86_64-glibc
  - aarch64-musl
  - aarch64-glibc