Update ancient pytest on python 3
Update ancient pytest on python 3

2.9 gives collection errors on python 3.7 due to PEP 479.

kmike/scrapy,pablohoffman/scrapy,ArturGaspar/scrapy,ArturGaspar/scrapy,finfish/scrapy,eLRuLL/scrapy,wujuguang/scrapy,eLRuLL/scrapy,pablohoffman/scrapy,starrify/scrapy,finfish/scrapy,kmike/scrapy,scrapy/scrapy,scrapy/scrapy,wujuguang/scrapy,Ryezhang/scrapy,kmike/scrapy,starrify/scrapy,ArturGaspar/scrapy,wujuguang/scrapy,elacuesta/scrapy,starrify/scrapy,dangra/scrapy,dangra/scrapy,elacuesta/scrapy,pawelmhm/scrapy,Ryezhang/scrapy,pawelmhm/scrapy,pablohoffman/scrapy,scrapy/scrapy,eLRuLL/scrapy,Ryezhang/scrapy,pawelmhm/scrapy,elacuesta/scrapy,dangra/scrapy,finfish/scrapy