all: replace []byte with []u8

vlib/crypto/rand/rand_solaris.c.v

@@ -13,7 +13,7 @@ const (
 )
 
 // read returns an array of `bytes_needed` random bytes read from the OS.
-pub fn read(bytes_needed int) ?[]byte {
+pub fn read(bytes_needed int) ?[]u8 {
 	mut buffer := unsafe { malloc_noscan(bytes_needed) }
 	mut bytes_read := 0
 	mut remaining_bytes := bytes_needed