Enable selector filter and add traffic_anomalies_alert as notification type

[Cyb3r-Jak3]

Adds selector filter
Adds traffic_anomalies_alert for notification policy types (not in the API yet but is valid through dashboard)

Fixes #2935

[github-actions]

changelog detected ✅

[jacobbednarz]

cc @jasoncabot

[jasoncabot]

This looks good to me, thanks for the change. I've also updated the OpenAPI spec too to add traffic_anomalies_alert

[jacobbednarz]

i fixed up the test assertion here in 0eec700 and now we're looking good!

TF_ACC=1 go test ./internal/sdkv2provider -v -run "^TestAccCloudflareNotificationPolicy_" -count 1 -timeout 120m -parallel 1
=== RUN   TestAccCloudflareNotificationPolicy_Basic
--- PASS: TestAccCloudflareNotificationPolicy_Basic (17.45s)
=== RUN   TestAccCloudflareNotificationPolicy_WithFiltersAttribute
--- PASS: TestAccCloudflareNotificationPolicy_WithFiltersAttribute (17.55s)
=== RUN   TestAccCloudflareNotificationPolicy_WithSelectorsAttribute
--- PASS: TestAccCloudflareNotificationPolicy_WithSelectorsAttribute (10.71s)
PASS
ok  	github.com/cloudflare/terraform-provider-cloudflare/internal/sdkv2provider	46.511s

[github-actions]

This functionality has been released in v4.21.0 of the Terraform Cloudflare Provider.

Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!