change default encoding for stringtochar/chartostring #408

Job	Run time
Build ubuntu-24.04-arm (aarch64) wheels	9m 18s
Build wheels for ARM64 on Windows	17m 8s
Build wheels for arm64 on macos-14	11m 18s
Build ubuntu-22.04 (x86_64) wheels	5m 40s
Build source distribution	39s
Build wheels for x86_64 on macos-15-intel	20m 45s
Build wheels for AMD64 on windows-latest	13m 21s
Show artifacts	9s
Publish to PyPI	0s
	1h 18m 18s

Provide feedback