Bump chart to 0.18.0 (#319)

Author: toddkazakov

charts/tidepool/Chart.yaml

@@ -1,7 +1,7 @@
 apiVersion: v2
 description: A Helm chart for Tidepool
 name: tidepool
-version: 0.17.7
+version: 0.18.0
 maintainers:
   - name: Todd Kazakov
     email: todd@tidepool.org