[scheduledqueryrules] Update targeting API Version to 2021-02-01-preview

The current API version of resource `scheduledqueryrules` used in Azure SDK for Go is [2018-04-16](https://github.com/Azure/azure-sdk-for-go/blob/ba766374b894413a94ee10f8729251369e6047a4/services/preview/monitor/mgmt/2021-07-01-preview/insights/scheduledqueryrules.go#L99). The latest version available in Azure REST API is [2021-02-01-preview](https://docs.microsoft.com/en-us/rest/api/monitor/scheduledqueryrule-preview/scheduled-query-rules/create-or-update#uri-parameters). This latest version is also used by [Azure CLI](https://github.com/Azure/azure-cli-extensions/blob/7043fb5940e41f5e288178724380dc2d14a00091/src/scheduled-query/azext_scheduled_query/vendored_sdks/azure_mgmt_scheduled_query/_configuration.py#L51). Please update the [targeting API version](https://github.com/Azure/azure-rest-api-specs/blob/main/specification/monitor/resource-manager/readme.md#tag-package-2021-09) of `scheduledqueryrules` to use `2021-02-01-preview`. Updating to this new version will allow us to create [stateful log alerts](https://docs.microsoft.com/en-us/azure/azure-monitor/alerts/alerts-unified-log#state-and-resolving-alerts) in Azure Monitor. This issue was created in this repository as requested by @lirenhe [here](https://github.com/Azure/azure-sdk-for-go/issues/15987#issuecomment-996442012)

Start with specification/monitor/resource-manager/readme.md and the scheduledqueryrules package mapping referenced by the 2021-09 tag. Trace the scheduledqueryrules specification and its targeting API version, then update it to 2021-02-01-preview. Done means the specification targets that version and the resulting API definition reflects it.

Written by the indexing model from the issue text.