[watsonx.ai] update restapi provider to latest supported version

[imprateeksh]

Description

The restapi provider should be updated to use the latest version and it appears some failures are seen while updating the restapi version. Current version is 1.20.0 and the latest version is 2.0.1

There is already a renovate PR opened for making this update (refer PR #149) but it is failing to update the version.

[imprateeksh]

Some references mentioning the same issue and solution used -

• Panic on ReadResource Mastercard/terraform-provider-restapi#287
• fix(deps): update terraform restapi to latest for the deployable architecture solution - abandoned #85 (comment)

[imprateeksh]

ignore_changes_to and ignore_all_server_changes were introduced as part of v2.0.0