Introduce RISC-V workflow build

[eshattow]

Hello, PyPI warehouse uploads for riscv64 architecture were enabled in the past year-or-such. Please consider to build and test and upload wheels for RISC-V riscv64 architecture. There are community runners sponsored by RISE RISC-V Runner professionally managed connection at no cost to the open source community: https://riseproject-dev.github.io/riscv-runner/

1. Decide if it is acceptable to add access to the "ubuntu-24.04-riscv" runner by the RISE RISC-V Runner add-on in GitHub marketplace for your repository
2. Update workflows to use version of cibuildwheel v3.4.1 and newer Bump version cibuildwheel v3.4.1 #2832
3. Add the runner label to the build matrix

Build statistics:
ubuntu-24.04-riscv, riscv64 8m 32s with 3 test failures

Related:
#2562 "linux: fix cpu_freq() when one cpufreq policy affects multiple CPUs"