postmarketos-base: Make NetworkManager conf more easily overridable (!260)

Later conf files override earlier ones. With this change, device specific
packages can ship their own NetworkManager configs that override the
postmarketos config.

Example: 10-samsung-p4wifi.conf would override 00-postmarketos.conf

main/postmarketos-base/APKBUILD

@@ -1,6 +1,6 @@
 pkgname=postmarketos-base
 pkgver=3
-pkgrel=21
+pkgrel=22
 pkgdesc="Meta package for minimal postmarketOS base"
 url="https://postmarketos.org"
 arch="noarch"
@@ -54,7 +54,7 @@ package() {
 		"$pkgdir"/etc/init.d/swapfile
 
 	install -D -m644 "$srcdir"/networkmanager.conf \
-		"$pkgdir"/etc/NetworkManager/conf.d/postmarketos.conf
+		"$pkgdir"/etc/NetworkManager/conf.d/00-postmarketos.conf
 
 	install -Dm755 "$srcdir"/devmappings.initd \
 		"$pkgdir"/etc/init.d/devmappings