rel: prep for 1.18.0 release (#229)

## Short description of the changes
- bump chart version
- update changelog

charts/refinery/CHANGELOG.md

@@ -1,5 +1,10 @@
 # Refinery Helm Chart Changelog
 
+## Refinery v1.18.0
+  - maint: Update refinery chart to use refinery [1.20.0](https://github.com/honeycombio/refinery/releases/tag/v1.20.0) (#227) | @TylerHelmuth
+    - This is a significant and exciting upgrade of Refinery.  For more details see [Refinery's Release notes](https://github.com/honeycombio/refinery/blob/main/RELEASE_NOTES.md#version-1200).
+  - chore: add nodeport to the service.yaml (#222) | @fchikwekwe
+
 ## Refinery v1.17.0
   - fix: Updated ordering of CPU/Memory resource metrics (#217) | @robiball
   - maint: Update HPAs to autoscaling/v2 (#215) | @robiball

charts/refinery/Chart.yaml

@@ -2,7 +2,7 @@ apiVersion: v2
 name: refinery
 description: Chart to deploy Honeycomb Refinery
 type: application
-version: 1.17.0
+version: 1.18.0
 appVersion: 1.20.0
 keywords:
   - refinery