upgrade terraform provider version to 3.12

[obeleh]

Code Review

Please consider the following checklist when reviewing this Pull Request.
More background and details here.

• Does the code actually solve the problem it was meant to solve?
• Is the code covered by unit tests? Integration tests?
• Does anything here need documentation? (Focus on why, not what.)
• Does any of this code deal with privacy sensitive information or affects security? Ask an additional reviewer.
• Is the code easy to understand and change in the future?
• Is the same code or concept duplicated? Find a balance between DRYness and readability.
• Does the code reasonably adhere to the Kabisa coding standards?
• Be kind.