Fix size of the RSA key in bits (#77)

Author: solracsf

content/5.other/2.containers.md

@@ -49,7 +49,7 @@ The image expects all configuration to be mounted at `/config`. At a minimum, th
 The `signing.key` can be generated using the following command:
 
 ```
-openssl genrsa -out path/to/signing.key 2018
+openssl genrsa -out path/to/signing.key 2048
 ```
 
 ## Networking