schema: Fix wrong type of CLTV in route

We were using `number` instead of `u32` which caused it to be
serialized to string with a decimal, which then would be rejected by
lightningd.

Changelog-Fixed: proto: Fixed a wrong number type being used in routes

Author: cdecker

.gitattributes

@@ -17,4 +17,4 @@ statements_gettextgen.po linguist-generated=true
 cln-grpc/proto/node.proto -text -diff linguist-generated=true
 cln-grpc/src/convert.rs -text -diff linguist-generated=true
 cln-rpc/src/model.rs -text -diff linguist-generated=true
-contrib/pyln-testing/pyln/testing/node_pb2.py linguist-generated=true
+contrib/pyln-testing/pyln/testing/node_pb2.py -text -diff linguist-generated=true

cln-grpc/proto/node.proto

@@ -20,7 +20,7 @@
       "description": ""
     },
     "cltv": {
-      "type": "number",
+      "type": "u32",
       "description": ""
     },
     "fromid": {