device-librecomputer-solitude: add myself as co-maintainer (MR 4602)

[ci:skip-vercheck] no feature changes

Signed-off-by: Ferass El Hafidi <vitali64pmemail@protonmail.com>
[ci:skip-build]: already built successfully in CI

device/testing/device-librecomputer-solitude/APKBUILD

 # Reference: <https://postmarketos.org/devicepkg>
 # Maintainer: Newbyte <newbyte@postmarketos.org>
+# Co-maintainer: Ferass El Hafidi <vitali64pmemail@protonmail.com>
 pkgname=device-librecomputer-solitude
 pkgdesc="Libre Computer AML-S905D3-CC"
 pkgver=0.1