Update .travis.yml
Update .travis.yml

Reverting change to 3.8 extra dependency environment.
elacuesta/scrapy,pablohoffman/scrapy,starrify/scrapy,scrapy/scrapy,pawelmhm/scrapy,starrify/scrapy,pawelmhm/scrapy,dangra/scrapy,pablohoffman/scrapy,dangra/scrapy,eLRuLL/scrapy,dangra/scrapy,elacuesta/scrapy,starrify/scrapy,pablohoffman/scrapy,scrapy/scrapy,elacuesta/scrapy,eLRuLL/scrapy,scrapy/scrapy,pawelmhm/scrapy,eLRuLL/scrapy