Update building.md

add missing pull lfs objects to avoid broke the build

git lfs fetch --all && git lfs pull && git submodule foreach --recursive 'git lfs fetch --all && git lfs pull'

Author: bdmstyle

docs/building.md

@@ -1,11 +1,17 @@
 # Building
 
-After cloning the repo, ensure all submodules are cloned.
+After cloning the repo ensure all submodules are cloned.
 
 ```
 git submodule update --init --checkout --recursive
 ```
 
+pull lfs objects
+
+```
+git lfs fetch --all && git lfs pull && git submodule foreach --recursive 'git lfs fetch --all && git lfs pull'
+```
+
 Dependencies can be installed with the provided scripts.
 
 ```