[mpact][compiler] add recursive to git submodule command

README.md

diff --git a/README.md b/README.md
index fa611b7..b2d0214 100644
--- a/README.md
+++ b/README.md
@@ -21,7 +21,7 @@
 ```shell
 git clone https://github.com/MPACT-ORG/mpact-compiler.git
 cd mpact-compiler
-git submodule update --init --progress
+git submodule update --init --recursive --progress
 ```
 
 All following commands assume you remain in the `mpact-compiler` directory.