Bump PyYAML dependency

Change-Id: Ia45f9c0299237506ab08a7ecb056683ec2474f03
Related-bug: PRODX-5769
diff --git a/requirements.txt b/requirements.txt
index 1b4a483..ce7be24 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -15,7 +15,7 @@
 prometheus-client==0.4.2
 pycparser==2.19
 pyOpenSSL==18.0.0
-PyYAML==3.13
+PyYAML==5.3.1
 requests==2.23.0
 simple-salesforce==0.74.2
 simple-settings==0.13.0