change default encoding for stringtochar/chartostring #411

Job	Run time
Build source distribution	54s
Build ubuntu-22.04 (x86_64) wheels	5m 48s
Build wheels for ARM64 on Windows	17m 39s
Build ubuntu-24.04-arm (aarch64) wheels	8m 20s
Build wheels for AMD64 on windows-latest	14m 55s
Build wheels for x86_64 on macos-15-intel	15m 40s
Build wheels for arm64 on macos-14	10m 34s
Show artifacts	9s
Publish to PyPI	0s
	1h 13m 59s

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