Increase time in test

Author: gusty

tests/FSharpPlus.Tests/Task.fs

@@ -333,10 +333,10 @@ module Task =
             let t =
                 monad' {
                     do! Task.Yield()
-                    Thread.Sleep(100)
+                    Thread.Sleep(500)
                 }
             sw.Stop()
-            require (sw.ElapsedMilliseconds < 50L) "sleep blocked caller"
+            require (sw.ElapsedMilliseconds < 450L) "sleep blocked caller"
             t.Wait()
 
         let failtest str = raise (TestException str)