update readme for 1.5 release
@@ -57,6 +57,7 @@ Enjoy!
### Releases
+* 2020-02-09, `v1.5.0`: stable release 1.5: improved free performance, small bug fixes.
* 2020-01-22, `v1.4.0`: stable release 1.4: improved performance for delayed OS page reset,
more eager concurrent free, addition of STL allocator, fixed potential memory leak.
* 2020-01-15, `v1.3.0`: stable release 1.3: bug fixes, improved randomness and [stronger
