community/podman: add go-md2man makedepends

While building this locally I noticed podman's makefile fetches
go-md2man from internet with a go install command, but we have
a package for this.
This also speeds up build times a bit.

community/podman/APKBUILD

@@ -2,7 +2,7 @@
 # Maintainer: Michał Polański <michal@polanski.me>
 pkgname=podman
 pkgver=4.1.1
-pkgrel=0
+pkgrel=1
 pkgdesc="Simple management tool for pods, containers and images"
 url="https://podman.io/"
 license="Apache-2.0"
@@ -29,6 +29,7 @@ makedepends="
 	go-md2man
 	btrfs-progs-dev
 	bash
+	go-md2man
 	"
 subpackages="
 	$pkgname-doc