add a note about rand to 0.1.42

Author: cuviper

RELEASES.md

@@ -3,12 +3,14 @@
 - [num-bigint now has its own source repository][num-356] at [rust-num/num-bigint][home].
 - [`lcm` now avoids creating a large intermediate product][num-350].
 - [`gcd` now uses Stein's algorithm][15] with faster shifts instead of division.
+- [`rand` support is now extended to 0.4][11] (while still allowing 0.3).
 
-**Contributors**: @cuviper, @Emerentius, @mhogrefe
+**Contributors**: @cuviper, @Emerentius, @ignatenkobrain, @mhogrefe
 
 [home]: https://github.com/rust-num/num-bigint
 [num-350]: https://github.com/rust-num/num/pull/350
 [num-356]: https://github.com/rust-num/num/pull/356
+[11]: https://github.com/rust-num/num-bigint/pull/11
 [15]: https://github.com/rust-num/num-bigint/pull/15