Bump config version (#1353)

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## Overview

Closes: #1323

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## Checklist

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- [x] New and updated code has appropriate documentation
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<!-- This is an auto-generated comment: release notes by coderabbit.ai
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## Summary by CodeRabbit

- **New Features**
- Updated the software to version 0.12.0, enhancing overall
functionality.

- **Documentation**
- Added new steps in the release process to ensure version consistency
across releases.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: Manav-Aggarwal

RELEASE.md

@@ -2,6 +2,7 @@
 
 ## Steps
 
+* Update config version in [config/defaults.go](https://github.com/rollkit/rollkit/blob/main/config/defaults.go)
 * Release new Rollkit version
 * Update [Rollkit/Cosmos-SDK](https://github.com/rollkit/cosmos-sdk) with the newly released Rollkit version
 * Release new Rollkit/Cosmos-SDK version

config/defaults.go

@@ -9,8 +9,9 @@ import (
 const (
 	// DefaultListenAddress is a default listen address for P2P client.
 	DefaultListenAddress = "/ip4/0.0.0.0/tcp/7676"
-	// Version is the current rollkit version and is used for checking RPC compatibility??
-	Version = "0.4.0"
+	// Version is the current rollkit version
+	// Please keep updated with each new release
+	Version = "0.12.0"
 )
 
 // DefaultNodeConfig keeps default values of NodeConfig