Explicitly specify the size of connection options

This makes it so specifying the wrong number of options would actually throw a compile time error.

src/main.zig

@@ -7,7 +7,7 @@ const SaprusPacketType = enum(u16) {
     connection = 0x00E9,
 };
 
-const SaprusConnectionOptions = packed struct {
+const SaprusConnectionOptions = packed struct(u8) {
     opt1: bool = false,
     opt2: bool = false,
     opt3: bool = false,