fix(README): notice to checkout the submodules

README.md

@@ -4,6 +4,12 @@ This repository contains my private PKGBUILDs. Some PKGBUILDs are also available
 in the [AUR Repository](https://aur.archlinux.org/packages/?K=volker.raschek&SeB=m).
 The compiled binaries can be pulled from my [repository](https://arch.cryptic.systems).
 
+If you want to clone this repository, don't forget to checkout the git submodules.
+
+```bash
+git submodule update --init --recursive
+```
+
 ## Import GPG Key
 
 Import and trust my GPG-Key to verify the gpg signed packages.