Feature: add udp timeout configuration

docs/content/routing/entrypoints.md

@@ -864,3 +864,35 @@ entryPoints:
     --entrypoints.websecure.address=:443
     --entrypoints.websecure.http.tls.certResolver=leresolver
     ```
+
+## UDP Options
+
+This whole section is dedicated to options, keyed by entry point, that will apply only to UDP routing.
+
+### Timeout
+
+_Optional, Default=3s_
+
+Timeout defines how long to wait on an idle session before releasing the related resources.
+The Timeout value must be greater than zero.
+
+```toml tab="File (TOML)"
+[entryPoints.foo]
+  address = ":8000/udp"
+
+    [entryPoints.foo.udp]
+      timeout = "10s"
+```
+
+```yaml tab="File (YAML)"
+entryPoints:
+  foo:
+    address: ':8000/udp'
+    udp:
+      timeout: 10s
+```
+
+```bash tab="CLI"
+entrypoints.foo.address=:8000/udp
+entrypoints.foo.udp.timeout=10s
+```

docs/content/routing/routers/index.md

@@ -982,8 +982,9 @@ So UDP "routers" at this time are pretty much only load-balancers in one form or
 	It basically means that some state is kept about an ongoing communication between a client and a backend,
 	notably so that the proxy knows where to forward a response packet from a backend.
 	As expected, a `timeout` is associated to each of these sessions,
-	so that they get cleaned out if they go through a period of inactivity longer than a given duration (that is hardcoded to 3 seconds for now).
-	Making this timeout configurable will be considered later if we get more usage feedback on this matter.
+	so that they get cleaned out if they go through a period of inactivity longer than a given duration. 
+	Timeout can be configured using the `entryPoints.name.udp.timeout` option as described 
+	under [entry points](../entrypoints/#udp-options).
 
 ### EntryPoints