Fix requirements file

api/requirements/base.txt

@@ -41,7 +41,7 @@ channels_redis~=3.3.0
 uvicorn[standard]~=0.14.0
 gunicorn~=20.1.0
 
-cryptography=>3.3.2
+cryptography>=3.3.2
 # requests-http-signature==0.0.3
 # clone until the branch is merged and released upstream
 git+https://github.com/agateblue/requests-http-signature.git@signature-header-support