Merge pull request #2468 from moble/vern6_premature_float64

Fix premature conversion to Float64 in Vern6

Author: ChrisRackauckas

lib/OrdinaryDiffEqVerner/src/verner_tableaus.jl

@@ -86,7 +86,7 @@ function Vern6ExtraStages(T, T2)
     a1008 = convert(T,
         -BigInt(15228408956329265381787438679500067) //
         BigInt(272520859345009876882656783678732))
-    a1009 = convert(T, 28587810357600962662801 / 1151340224617184234295192)
+    a1009 = convert(T, 28587810357600962662801 // 1151340224617184234295192)
     # Extra stages for Order 6
     c11 = convert(T2, 207 // 250)
     a1101 = convert(T,