chore: pin frontend image to v0.2.0

Use the tagged v0.2.0 release of climate-ref-frontend instead of
tracking the mutable main tag.

Author: lewisjared

helm/values.yaml

@@ -9,7 +9,7 @@ api:
   image:
     repository: ghcr.io/climate-ref/climate-ref-frontend
     pullPolicy: IfNotPresent
-    tag: main
+    tag: v0.2.0
 
   env:
     ENVIRONMENT: production