Fix Github Actions failure (#290)

Context: yaml/pyyaml#478

Let's see if this fixes the Github Actions failure

Author: Nikolas De Giorgis

requirements.txt

@@ -1,7 +1,7 @@
 docker==4.2.0
 kubernetes==11.0.0
 jinja2==2.11.2
-PyYAML==5.3.1
+PyYAML==5.4.1
 black==20.8b1
 mypy==0.782
 tqdm==v4.49.0