Change step in range function

src/Julia/Problem007.jl

@@ -12,7 +12,7 @@ function is_prime(n)
     if n % 2 == 0 && n > 2
         return false
     end
-    for i in 3:round(sqrt(n) + 1)
+    for i in 3:2:2:round(sqrt(n) + 1)
         if n % i == 0
             return false
         end