Fix Rust compiler build error (Kubernetes dependency) (#471)

Update pip version during CircleCI setup stage to resolve Rust compiler build error (as suggested in https://cryptography.io/en/latest/faq.html#installing-cryptography-fails-with-error-can-not-find-rust-compiler)

.circleci/config.yml

@@ -22,6 +22,7 @@ aliases:
     run:
       name: Prepare aws cli
       command: |
+        sudo pip install --upgrade pip
         sudo pip install awscli pytest kubernetes==8.0.0b1
 
         $(aws ecr get-login --no-include-email --region us-west-2)