update readme

Author: joe-niland

README.yaml

@@ -17,7 +17,7 @@ license: "APACHE2"
 copyrights:
   - name: "DeployMode Pty Ltd"
     url: "https://www.deploymode.com/"
-    year: "2020-2023"
+    year: "2020"
 
 # Canonical GitHub repo
 github_repo: deploymode/terraform-aws-client-vpn