Update dependency kubernetes to v19

requirements.txt

@@ -46,7 +46,7 @@ jinja2==3.0.2
     #   jinja2-base64-filters
 jinja2-base64-filters==0.1.4
     # via -r requirements.in
-kubernetes==18.20.0
+kubernetes==19.15.0
     # via -r requirements.in
 markupsafe==2.0.1
     # via jinja2