Update dependency org.webjars.npm:redoc to v2.1.3

Author: renovate[bot]

javalin-demo/gradle.properties

@@ -5,7 +5,7 @@ org.gradle.caching=true
 
 # Code
 javalinVersion=5.6.3
-webjarredocVersion=2.0.0
+webjarredocVersion=2.1.3
 unrestJavaVersion=3.14.5
 prometheusVersion=0.16.0
 j2htmlVersion=1.6.0