fix: do not suggest anything for SYSTEMNAME

new SYSTEMNAME is chosen on purpose.

README.md

@@ -53,7 +53,7 @@ Add the project repository to your Spack environment:
 spack repo add ebrains-spack-builds
 ```
 
-Define your site-specific configurations, e.g. choose `ebrainslab`:
+Define your site-specific configurations:
 ```
 export SYSTEMNAME=<your-system-name>
 mkdir ebrains-spack-builds/site-config/$SYSTEMNAME