update README.md
update README.md

Signed-off-by: dxjia <e0d4cee866ae19e990e1b8c17e277b1b2873e0ab@sina.cn>

dxjia/ffmpeg-commands-executor-library,dxjia/ffmpeg-jni-sample,dxjia/ffmpeg-commands-executor-library,dxjia/ffmpeg-commands-executor-library,dxjia/ffmpeg-commands-executor-library,dxjia/ffmpeg-jni-sample,dxjia/ffmpeg-jni-sample