libre: Add mkinitcpio mkinitcpio-30-2.parabola2-any.src.tar.gz source code
    
    The process of packages releases makes it very easy to
    forget to push a package or its source code to git:
    - A developer can push to abslibre and forget to build the
      package, or that developer might want to build the package
      later on for various reasons.
    - A developer can also push the package and forget to push
      the corresponding git commits to abslibre.
    
    I often am in the first case, but here we are in the later
    case.
    
    Fortunately the process of packages releases also makes it easy
    to find that source code.
    
    The source code of libre/mkinitcpio can be found here:
    https://repo.parabola.nu/sources/parabola/mkinitcpio-30-2.parabola1-any.src.tar.gz
    https://repo.parabola.nu/sources/parabola/mkinitcpio-30-2.parabola1-any.src.tar.gz.sig
    
    And we can even verify its signature:
        $ gpg --verify mkinitcpio-30-2.parabola2-any.src.tar.gz.sig
        gpg: assuming signed data in 'mkinitcpio-30-2.parabola2-any.src.tar.gz'
        gpg: Signature made sam. 06 nov. 2021 03:42:02 CET
        gpg:                using RSA key FBCC5AD7421197B7ABA72853908710913E8C7778
        gpg: Good signature from "bill-auger <bill-auger@peers.community>" [unknown]
        gpg:                 aka "bill-auger <mr.j.spam.me@gmail.com>" [unknown]
        gpg:                 aka "bill-auger <bill-auger@programmer.net>" [unknown]
        gpg:                 aka "[jpeg image of size 6017]" [unknown]
        gpg: Note: This key has expired!
        Primary key fingerprint: 3954 A7AB 837D 0EA9 CFA9  7989 25DB 7D9B 5A8D 4B40
             Subkey fingerprint: FBCC 5AD7 4211 97B7 ABA7  2853 9087 1091 3E8C 7778
    
    So we can safely import the source back in abslibre.
    
    The archive has a bit more than needed for this specific situation:
        $ tar tf ../mkinitcpio-30-2.parabola2-any.src.tar.gz
        mkinitcpio/
        mkinitcpio/mkinitcpio-30.tar.gz
        mkinitcpio/PKGBUILD
        mkinitcpio/.SRCINFO
        mkinitcpio/mkinitcpio.install
        mkinitcpio/mkinitcpio-30.tar.gz.sig
        mkinitcpio/9001-udev.patch
    So I only used the PKGBUILD, mkinitcpio.install and
    9001-udev.patch files here as we don't commit the .SRCINFO
    or source tarballs to git in Parabola.
    
    Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>