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add link to release notes

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nicozhang/pyspider,qiulimao/weblocust,luotao19861229/pyspider,wangjun/pyspider,snakeliwei/pyspider,wonderay/pyspider,binux/pyspider,VDuda/pyspider,lashwang/pyspider,luoq/pyspider,e-dorigatti/pyspider,snakeliwei/pyspider,luotao19861229/pyspider,binux/pyspider,e-dorigatti/pyspider,lashwang/pyspider,qiulimao/weblocust,binux/pyspider,wangjun/pyspider,lashwang/pyspider,VDuda/pyspider,wonderay/pyspider,eromoe/pyspider,luoq/pyspider,wangjun/pyspider,wonderay/pyspider,qiulimao/weblocust,luotao19861229/pyspider,nicozhang/pyspider,e-dorigatti/pyspider,eromoe/pyspider,eromoe/pyspider,VDuda/pyspider,snakeliwei/pyspider,luoq/pyspider,nicozhang/pyspider