Revise README (#23)

Author: wata727

CHANGELOG.md

@@ -1,3 +1,5 @@
 ## 0.1.0 (2022-09-08)
 
 Initial release 🎉
+
+The rules have been migrated from TFLint v0.39.3. See the TFLint's CHANGELOG for a history of previous changes to these rules.

README.md

@@ -3,8 +3,6 @@
 [![GitHub release](https://img.shields.io/github/release/terraform-linters/tflint-ruleset-terraform.svg)](https://github.com/terraform-linters/tflint-ruleset-terraform/releases/latest)
 [![License: MPL 2.0](https://img.shields.io/badge/License-MPL%202.0-blue.svg)](LICENSE)
 
-**This ruleset is a work in progress. Not ready for use yet.**
-
 TFLint ruleset plugin for Terraform Language
 
 This ruleset focus on possible errors and best practices about Terraform Language.