add observatory scheduled test resource

[broswen]

Adds a Terraform resource to schedule an Observatory page test.
https://developers.cloudflare.com/api/operations/speed-create-scheduled-test

Depends on bug fix: cloudflare/cloudflare-go#1412
And also depends on updating cloudflare-go.

[github-actions]

changelog detected ✅

[github-actions]

This project handles dependency version bumps (including upstream changes from cloudflare-go) independently of the standard PR process using automation. This allows the dependency upgrades to land without causing merge conflicts in multiple branches and handled in a consistent way. The exception to this is security related dependency upgrades but they should be co-ordinated with the maintainer team privately.

Please remove the changes to the go.mod or go.sum files from this PR in order to proceed with review and merging.

[github-actions]

Marking this pull request as stale due to 14 days of inactivity. This helps our maintainers find and focus on the active pull requests. If this pull request receives no comments in the next 7 days it will automatically be closed. Maintainers can also remove the lifecycle/stale label.
If this pull request was automatically closed and you feel this pull request should be reopened, we encourage creating a new pull request linking back to this one for added context. Thank you!

[jacobbednarz]

@broswen If you clean up the Go module files, this should apply blow

[jacobbednarz]

lgtm thanks! 🏅

TF_ACC=1 go test ./internal/sdkv2provider -v -run "^TestAccCloudflareObservatoryScheduledTest_" -count 1 -timeout 120m -parallel 1
=== RUN   TestAccCloudflareObservatoryScheduledTest_Create
=== PAUSE TestAccCloudflareObservatoryScheduledTest_Create
=== CONT  TestAccCloudflareObservatoryScheduledTest_Create
--- PASS: TestAccCloudflareObservatoryScheduledTest_Create (8.67s)
PASS
ok  	github.com/cloudflare/terraform-provider-cloudflare/internal/sdkv2provider	9.403s

[github-actions]

This functionality has been released in v4.17.0 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!