The v1.2.1 release, "Hari Seldon", contains some new API-methods and a lot of improvements under the hood and in the surrounding infrastructure.

• OSS-fuzz integration has finally happened, as of (#98) and https://github.com/google/oss-fuzz/pull/6497. The uint256 library is now continuously fuzzed by the fine folks at OSS-Fuzz.
• Optimised modular arithmetic targeting elliptic curve operations (#86). This was a major overhaul and complete rewrite of the modular arithmetic operations.
• Added DivMod() (#113)
• Added MulDivOverflow() (#110)
• Added Sqrt() (#104)
• Improvements ot Cmp() (#85)
• Test improvements (#112, #95, #93, #92, #91, #89, #88)

Thanks to all contributors to this release: @holiman, @chfast,@daosvik, @Planxnx and @fyrchik.