mdbx: release v0.10.4

Acknowledgements:
-----------------
 - [Artem Vorotnikov](https://github.com/vorot93) for support [Rust wrapper](https://github.com/vorot93/mdbx-rs).
 - [Andrew Ashikhmin](https://github.com/yperbasis) for contributing to C++ API.

Fixes:
------
 - Fixed possibility of looping update GC during transaction commit (no public issue since the problem was discovered inside [Positive Technologies](https://www.ptsecurity.ru).
 - Fixed `#pragma pack` to avoid provoking some compilers to generate code with [unaligned access](https://github.com/erthink/libmdbx/issues/235).
 - Fixed `noexcept` for potentially throwing `txn::put()` of C++ API.

Minors:
-------
 - Added stochastic test script for checking small transactions cases.
 - Removed extra transaction commit/restart inside test framework.
 - In debugging builds fixed a too small (single page) by default DB shrink threshold.

ChangeLog.md

@@ -20,7 +20,7 @@ ChangeLog
  - Packages for [Astra Linux](https://astralinux.ru/), [ALT Linux](https://www.altlinux.org/), [ROSA Linux](https://www.rosalinux.ru/), etc.
 
 
-## v0.10.4 (scheduled 2021-10-12)
+## v0.10.4 at 2021-10-10
 
 Acknowledgements:
 

appveyor.yml

@@ -1,4 +1,4 @@
-version: 0.10.3.{build}
+version: 0.10.4.{build}
 
 environment:
   matrix: