Make network_mode and networks mutually exclusive attributes

Signed-off-by: Laura Brehm <[email protected]>

Author: laurazard

05-services.md

@@ -1060,6 +1060,9 @@ specification define specific values which MUST be implemented as described if s
     network_mode: "service:[service name]"
 ```
 
+When set, `networks` attribute is not allowed and a Compose implementation SHOULD reject any
+Compose file containing both attributes
+
 ### networks
 
 `networks` defines the networks that service containers are attached to, referencing entries under the

spec.md

@@ -1311,6 +1311,9 @@ specification define specific values which MUST be implemented as described if s
     network_mode: "service:[service name]"
 ```
 
+When set, `networks` attribute is not allowed and a Compose implementation SHOULD reject any
+Compose file containing both attributes
+
 ### networks
 
 `networks` defines the networks that service containers are attached to, referencing entries under the