Add Rule for Deprecated partition_key_path in azurerm_cosmosdb_sql_container

[kierzo89]

This pull request introduces a new custom rule to detect the use of the deprecated partition_key_path attribute in the azurerm_cosmosdb_sql_container resource. The rule warns users to replace partition_key_path with the updated partition_key_paths attribute, which will be required in future versions of the AzureRM provider.

Key Changes:
New Rule: azurerm_cosmosdb_sql_container_deprecated_partition_key_path:
Added a rule to identify the deprecated partition_key_path in azurerm_cosmosdb_sql_container Terraform resources.
The rule emits a warning when partition_key_path is found, suggesting to update to partition_key_paths.

Test Coverage:
Added test cases to validate that the rule correctly detects partition_key_path and emits the appropriate warning.
Ensured that valid configurations using partition_key_paths pass without any issues.

Benefits:
Ensures Terraform configurations are updated according to the latest AzureRM provider requirements.
Helps users avoid breaking changes in future AzureRM versions by warning about deprecated attributes.

Next Steps:
Users are encouraged to update their Terraform configurations by replacing partition_key_path with partition_key_paths in affected resources.

[wata727]

Thank you for opening this PR.

I think rules to warn about deprecations like this would be useful, but I'm not sure if they should be done in TFLint.
Terraform already has a feature for notifying users of deprecated attributes, so using that would probably be the most reliable way to inform users of the deprecation.
https://developer.hashicorp.com/terraform/plugin/framework/deprecations#provider-attribute-rename

Please let me know if there is a reason why you can't use this or why TFLint is a better choice.