Fixing version in README (#35)

Author: cybcon

README.md

@@ -8,7 +8,8 @@ Container image: [DockerHub](https://hub.docker.com/r/oitc/modbus-server)
 
 # Supported tags and respective `Dockerfile` links
 
-* [`latest`, `1.3.0`](https://github.com/cybcon/modbus-server/blob/v1.3.0/Dockerfile)
+* [`latest`, `1.3.1`](https://github.com/cybcon/modbus-server/blob/v1.3.1/Dockerfile)
+* [`1.3.0`](https://github.com/cybcon/modbus-server/blob/v1.3.0/Dockerfile)
 * [`1.2.0`](https://github.com/cybcon/modbus-server/blob/v1.2.0/Dockerfile)
 * [`1.1.5`](https://github.com/cybcon/modbus-server/blob/v1.1.5/Dockerfile)
 * [`1.1.4`](https://github.com/cybcon/modbus-server/blob/v1.1.4/Dockerfile)