riscof validateyaml fails due to special characters in schema_isa.yaml

[silabs-kjetil]

Hi,

I am seeing the same errors as have been previously reported in this issue #17.

> riscof validateyaml --config=config.ini
    INFO | ****** RISCOF: RISC-V Architectural Test Framework 1.25.3 *******
    INFO | using riscv_isac version : 0.18.0
    INFO | using riscv_config version : 3.17.0
...
ruamel.yaml.reader.ReaderError: unacceptable character #x0080: special characters are not allowed
  in "/work/kjostera/experiments/riscof/venv_py310/lib/python3.10/site-packages/riscv_config/schemas/schema_isa.yaml", position 18507

Here are some more details on the environment where this has been reproduced.

> python3 --version
Python 3.10.6
> riscof --version
RISC-V Architectural Test Framework., version 1.25.3
> riscv-config --version
Version: 3.17.0

This is due to the special tick characters that are used in multiple description fields. Note that I do not see this error on all platforms so there might be some platform dependent encoding configurations that play a part in this issue. I can try to create a PR which replaces these characters with the ' character instead.

[silabs-kjetil]

PR can be found in the riscv-config project: riscv-software-src/riscv-config#168