ci: use apply rather than sync for deploys

We recently added several new manifests to the regular deployments, and
since making this change, preview deploys occasionally get gummed up.
A manual 'apply' action run locally straightens it out. The long-term
solution should be more intelligent wait-for-ready logic in the deploy
actions, but until then, let's do the bare minimum to keep things
working smoothly.

deployments/ci.sh

@@ -49,8 +49,7 @@ function helm_uninstall() {
 # as necessary. Will *not* replace certain durable resources like
 # the LoadBalancer Service objects, which are annotated with helm.sh/resource-policy=keep.
 function helm_install() {
-    # TODO: make sure helmfile is present in ci environemnt.
-    helmfile sync -f "$HELMFILE_MANIFEST" --args \
+    helmfile apply -f "$HELMFILE_MANIFEST" --args \
         --set="image.tag=${PENUMBRA_VERSION}"
 }