main/postmarketos-initramfs-minimal: don't hard-code libz path (MR 5610)

It's the work of the mkinitfs to fetch the library. This was initially
introduced in c7c2b2d0 and its use-case
is non-existent today as osk-sdl is gone. In addition, the mkinitfs
rework Clayton did some time ago correctly detects libraries needed for
binaries, exactly so we don't need to pull this in manually!

[ci:skip-build]: already built successfully in CI

main/postmarketos-initramfs-minimal/00-initramfs-extra-base.files

-/usr/lib/libz.so.1
 /sbin/btrfs
 /sbin/dmsetup
 /sbin/e2fsck

main/postmarketos-initramfs-minimal/APKBUILD

@@ -2,7 +2,7 @@
 # only be used on devices that do not have space for the full size ramdisk.
 pkgname=postmarketos-initramfs-minimal
 pkgver=2.8.0
-pkgrel=2
+pkgrel=3
 pkgdesc="Deprecated minimal initramfs for space constrained devices"
 url="https://postmarketos.org"
 options="!check"  # no tests
@@ -90,7 +90,7 @@ sha512sums="
 59be0649ed87a72d93624bd8a2e3f8c99a0f32f7b7a26f99436de782beba55671472c269eeee86440efc87e0d7148a0bb335fa537791092e73878ca21330544a  00-default.modules
 9c0e8f6f61d5da191e03a1aa9d5d0ceb5baf1eae6dbb9bfb0af59817783525119ac8394b135f303f7b6434a3eab0b49185fb90379e06823db847a4999c75ce33  00-initramfs-base.dirs
 ab41b45b0613f25a61114ed8c8b92bc53c60838f6e2e0ba18c76e5369b2984e6023a0661887692673aca3f647f268c468a468f6b1ac424cfee609017a89481dd  00-initramfs-base.files
-986a51f280876509655d91a36c9b323898c64d663cdf000dcf87eb1867c561b6c6a4c0f208bfa0b7e751459a96cd4298d48dadabd3b7a3fe7f8a4d19a726c8b6  00-initramfs-extra-base.files
+fb8acfff431f8f8a8af7770de7cbcf8d8e31e95235116f1d65bfa6aa222d2d48d190dfd12d86f715c8b07195250ea13d58d0dc65c46913df807eac8b20384f6b  00-initramfs-extra-base.files
 102cb49a5b44282afee7808945c69e9bb9310677efeefc681d92217f0399a90fcbb37eb9ac7aed89cc27c324780298c7c2de6de2bdb89a77499faad1c312e539  init.sh
 3e3cb29eabf9ee4c8dbd7ff2366aa8cea5f44b11b04df060d7841e9b8f25c85f0a2b19838b177a8b651f2b3c8b69135d36603534382c54736596d0bfa429ed87  init_functions.sh
 ba3275a9af788c7c782322a22a0f144d5e50e3498ea6886486a29331f23ae89cd32d500a3635cfa7cab369afba92edc18aeca64ccbf0cd589061cce23d15b46c  unudhcpd.conf