Install couchbase header files while running python3.6 build on CI (#216)

Author: Andrew Slotin

.circleci/config.yml

@@ -236,6 +236,10 @@ jobs:
           command: |
             sudo apt-get update
             sudo apt install lsb-release -y
+            curl -O https://packages.couchbase.com/releases/couchbase-release/couchbase-release-1.0-6-amd64.deb
+            sudo dpkg -i ./couchbase-release-1.0-6-amd64.deb
+            sudo apt-get update
+            sudo apt install libcouchbase-dev -y
             python -m venv venv
             . venv/bin/activate
             pip install -U pip