Release v0.4.2 Boosts Vyper with New Builtins and Optimizations

v0.4.2 adds raw_create() builtin for more generic Vyper factories. sqrt() moved to pure Vyper module after refactor, enabling more stdlib functionality. Venom pipeline gains CSE and dead-store elimination, shifts calling convention items to stack. Benchmark contracts shrink by 5%. Two low severity GHSAs resolved. Contributors @2xic, @iamslown, @Romain-Geissler-1A, and @crebsy debut. Full notes on Vyper docs.