Add setproduct function to the bake HCL

As explained in the following link, it's a very useful function.

https://www.terraform.io/docs/configuration/functions/setproduct.html#finding-combinations-for-for_each
Signed-off-by: Felipe Santos <felipecassiors@gmail.com>

bake/hcl.go

@@ -95,6 +95,7 @@ var (
 		"rsadecrypt":             crypto.RsaDecryptFunc,
 		"sethaselement":          stdlib.SetHasElementFunc,
 		"setintersection":        stdlib.SetIntersectionFunc,
+		"setproduct":             stdlib.SetProductFunc,
 		"setsubtract":            stdlib.SetSubtractFunc,
 		"setsymmetricdifference": stdlib.SetSymmetricDifferenceFunc,
 		"setunion":               stdlib.SetUnionFunc,