Update min/max seconds for add-time (#364)

min     1 ->  5
max 86400 -> 60

Trying to give 1 second results in 5 seconds.
Trying to give 86400 results in 60 seconds.

(Which corresponds to what can be found in
 modules/round/src/main/Moretimer.scala
...
 private val minTime = 5.seconds
 private val maxTime = 60.seconds
...
)

doc/specs/tags/challenges/api-round-gameId-add-time-seconds.yaml

@@ -19,8 +19,8 @@ post:
       description: How many seconds to give
       schema:
         type: string
-        minimum: 1
-        maximum: 86400
+        minimum: 5
+        maximum: 60
       required: true
   responses:
     "200":