Merge pull request #669 from pymongo/master

Make postgres protocol version value more readable

postgres-protocol/src/message/frontend.rs

@@ -260,7 +260,8 @@ where
     I: IntoIterator<Item = (&'a str, &'a str)>,
 {
     write_body(buf, |buf| {
-        buf.put_i32(196_608);
+        // postgres protocol version 3.0(196608) in bigger-endian
+        buf.put_i32(0x00_03_00_00);
         for (key, value) in parameters {
             write_cstr(key.as_bytes(), buf)?;
             write_cstr(value.as_bytes(), buf)?;