Update release workflow to build dockerhub images

[slimslenderslacks]

This PR adds one step to the release workflow to dispatch an event to request linux/arm64 and linux/amd64 images for each of the servers (tagged by release).

Description

Motivation and Context

This is to keep mcp server releases in sync with the tags hosted in the public dockerhub repo: https://hub.docker.com/u/mcp

How Has This Been Tested?

We have tested this repository dispatch event by using a test repo as a kind of "client". We will need to verify that everything worked end to end when we do the next release.

Breaking Changes

No. However, this will create new tags for users that are running mcp servers using docker.
This change does however meant that running servers like mcp/puppeteer:latest will mean that latest changes after new release. Release tags will only change if this GitHub deletes a release and builds it again with this workflow.

Checklist

• I have read the MCP Protocol Documentation
• My changes follows MCP security best practices
• I have updated the server's README accordingly
• I have tested this with an LLM client
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have documented all environment variables and configuration options

Additional context

This change only impacts the release workflow (GitHub actions).