[Docs] Extract release documentation to RELEASE.md

A README is generally best kept focused on information that is most valuable to users.
For that reason, release procedures that are not relevant to end users have been moved to
a separate RELEASE.md file.

Author: koic

README.md

@@ -925,16 +925,3 @@ The client provides a wrapper class for tools returned by the server:
 - `MCP::Client::Tool` - Represents a single tool with its metadata
 
 This class provides easy access to tool properties like name, description, input schema, and output schema.
-
-## Releases
-
-This gem is published to [RubyGems.org](https://rubygems.org/gems/mcp)
-
-Releases are triggered by PRs to the `main` branch updating the version number in `lib/mcp/version.rb`.
-
-1. **Update the version number** in `lib/mcp/version.rb`, following [semver](https://semver.org/)
-1. **Update CHANGELOG.md**, backfilling the changes since the last release if necessary, and adding a new section for the new version, clearing out the Unreleased section
-1. **Create a PR and get approval from a maintainer**
-1. **Merge your PR to the main branch** - This will automatically trigger the release workflow via GitHub Actions
-
-When changes are merged to the `main` branch, the GitHub Actions workflow (`.github/workflows/release.yml`) is triggered and the gem is published to RubyGems.