Update api versions in guides

docs/guides/helmreleases.md

@@ -225,7 +225,7 @@ the `gotk-system` to start receiving notifications about the Helm
 release:
 
 ```yaml
-apiVersion: notification.toolkit.fluxcd.io/v1alpha1
+apiVersion: notification.toolkit.fluxcd.io/v1beta1
   kind: Alert
   metadata:
     generation: 2
@@ -267,7 +267,7 @@ kubectl -n gotk-system create secret generic webhook-token \
 When using [Harbor](https://goharbor.io/) as your Helm repository, you can define a receiver with:
 
 ```yaml
-apiVersion: notification.toolkit.fluxcd.io/v1alpha1
+apiVersion: notification.toolkit.fluxcd.io/v1beta1
 kind: Receiver
 metadata:
   name: helm-podinfo

docs/guides/mozilla-sops.md

@@ -128,7 +128,7 @@ spec:
 Kustomization manifest:
 
 ```yaml
-apiVersion: kustomize.toolkit.fluxcd.io/v1alpha1
+apiVersion: kustomize.toolkit.fluxcd.io/v1beta1
 kind: Kustomization
 metadata:
   name: my-secrets

docs/guides/notifications.md

@@ -33,7 +33,7 @@ it can be a Slack, Microsoft Teams, Discord or Rocket webhook URL.
 Create a notification provider for Slack by referencing the above secret:
 
 ```yaml
-apiVersion: notification.toolkit.fluxcd.io/v1alpha1
+apiVersion: notification.toolkit.fluxcd.io/v1beta1
 kind: Provider
 metadata:
   name: slack
@@ -57,7 +57,7 @@ Elasticsearch, CloudWatch, Stackdriver, etc.
 Create an alert definition for all repositories and kustomizations:
 
 ```yaml
-apiVersion: notification.toolkit.fluxcd.io/v1alpha1
+apiVersion: notification.toolkit.fluxcd.io/v1beta1
 kind: Alert
 metadata:
   name: on-call-webapp
@@ -137,7 +137,7 @@ Creating a git provider is very similar to creating other types of providers.
 The only caveat being that the provider address needs to point to the same
 git repository as the Kustomization resource refers to.
 ```yaml
-apiVersion: notification.toolkit.fluxcd.io/v1alpha1
+apiVersion: notification.toolkit.fluxcd.io/v1beta1
 kind: Provider
 metadata:
   name: podinfo
@@ -149,7 +149,7 @@ spec:
   secretRef:
     name: github
 ---
-apiVersion: notification.toolkit.fluxcd.io/v1alpha1
+apiVersion: notification.toolkit.fluxcd.io/v1beta1
 kind: Alert
 metadata:
   name: podinfo

docs/guides/webhook-receivers.md

@@ -89,7 +89,7 @@ kubectl -n gotk-system create secret generic webhook-token \
 Create a receiver for GitHub and specify the `GitRepository` object:
 
 ```yaml
-apiVersion: notification.toolkit.fluxcd.io/v1alpha1
+apiVersion: notification.toolkit.fluxcd.io/v1beta1
 kind: Receiver
 metadata:
   name: webapp