[Snyk] Security upgrade pyyaml from 4.2b1 to 5.3.1#4

Open

snyk-bot wants to merge 1 commit intomasterfrom

snyk-fix-f1c16d601fa23874b0f4ecbb06562026

Commits on Apr 1, 2020

fix: requirements.txt to reduce vulnerabilities
snyk-bot
committed