chore: prepare chart release 1.4.0 (#271)

Author: zerok

charts/k6-loadtester/Chart.yaml

@@ -2,8 +2,8 @@ apiVersion: v2
 name: k6-loadtester
 description: Flagger webhook using k6 to do load testing of the canary before rolling out traffic
 type: application
-version: 1.3.3
-appVersion: "v0.3.3"
+version: 1.4.0
+appVersion: "v0.4.0"
 sources:
   - https://github.com/grafana/flagger-k6-webhook
 keywords:
@@ -17,4 +17,4 @@ maintainers:
 annotations:
   artifacthub.io/changes: |-
     - kind: updated
-      description: Update appVersion to v0.3.3
+      description: Update appVersion to v0.4.0