src: lib: PWM: Add set_pwm_channels_duty_cycle for Python and C #237

Job	Run time
quick-tests	1m 39s
version-manager	18s
build-cpp (armv7-unknown-linux-gnueabihf)	55s
build-python (aarch64, auto)	4m 1s
build-cpp (aarch64-unknown-linux-gnu)	1m 1s
build-python (aarch64, musllinux_1_1)	2m 35s
deploy-doc	2m 2s
build-cpp (armv7-unknown-linux-musleabihf)	1m 7s
build-python (armv7, auto)	4m 22s
build-python (armv7, musllinux_1_1)	2m 41s
build-cpp (aarch64-unknown-linux-musl)	1m 9s
raspberry-test-python	39s
python-release-pypi	0s
release-assets	0s
	22m 29s

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