main/bootmac: upgrade to v0.4.0 (MR 4665)

Added generate-only mode

main/bootmac/APKBUILD

 # Maintainer: Dylan Van Assche <me@dylanvanassche.be>
 pkgname=bootmac
-pkgver=0.2.1
+pkgver=0.4.0
 pkgrel=0
 pkgdesc="Configure MAC addresses at boot"
 url="https://gitlab.com/postmarketOS/bootmac"
@@ -19,5 +19,5 @@ package() {
 }
 
 sha512sums="
-f99bb1645c72ddb556a0c9d61a9a20d189d13c981caca4216f9c9876db138464c42e3870108a6ab7a5f06e9b5dfefb06b1e43aa1175f7c48030277bc028c33a5  bootmac-v0.2.1.tar.gz
+7d73e348f1ea1ff7a867e54848f754e34e3b2c7bd73f7fd09e2f68f8db0dba4bc7b3ea7cc713d0e2b67b7d67363d58c636656fd3cd336898b731c099fbb49c8b  bootmac-v0.4.0.tar.gz
 "