feat: background-postion支持百分比 #190

Job	Run time
stable - x86_64-apple-darwin - node@18	1m 30s
stable - x86_64-pc-windows-msvc - node@18	3m 57s
stable - x86_64-unknown-linux-gnu - node@18	4m 16s
stable - x86_64-unknown-linux-musl - node@18	6m 27s
stable - aarch64-apple-darwin - node@18	1m 41s
stable - aarch64-unknown-linux-gnu - node@18	2m 41s
stable - armv7-unknown-linux-gnueabihf - node@18	1m 32s
stable - aarch64-linux-android - node@18	1m 50s
stable - armv7-linux-androideabi - node@18	1m 41s
stable - aarch64-unknown-linux-musl - node@18	6m 32s
Test bindings on armv7-unknown-linux-gnueabihf - node@16	52s
Test bindings on Linux-x64-gnu - node@16	25s
Test bindings on armv7-unknown-linux-gnueabihf - node@18	50s
Test bindings on aarch64-unknown-linux-musl - node@	52s
Test bindings on Linux-x64-gnu - node@18	19s
Test bindings on aarch64-unknown-linux-gnu - node@16	2m 0s
Test bindings on aarch64-unknown-linux-gnu - node@18	2m 5s
Test bindings on x86_64-unknown-linux-musl - node@16	18s
Build universal macOS binary	17s
Test bindings on x86_64-unknown-linux-musl - node@18	18s
Publish	14s
	40m 37s

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