Bump tensorflow from 1.0.0 to 1.15.2 in /intro-to-rnns#21

dependabot[bot] wants to merge 1 commit intomasterzhulingchen/deep-learning:masterfrom

dependabot/pip/intro-to-rnns/tensorflow-1.15.2zhulingchen/deep-learning:dependabot/pip/intro-to-rnns/tensorflow-1.15.2Copy head branch name to clipboard