Move releases.md and update the deployment image reference from latest to main (#369)

<!-- Provide a brief summary of your changes -->

## Motivation and Context
<!-- Why is this change needed? What problem does it solve? -->
The following PR addresses the feedback comments from #366 

## How Has This Been Tested?
<!-- Have you tested this in a real application? Which scenarios were
tested? -->

## Breaking Changes
<!-- Will users need to update their code or configurations? -->
No
## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [x] Documentation update

## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [ ] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [ ] My code follows the repository's style guidelines
- [ ] New and existing tests pass locally
- [ ] I have added appropriate error handling
- [ ] I have added or updated documentation as needed

## Additional context
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-->

Signed-off-by: Radoslav Dimitrov <radoslav@stacklok.com>

deploy/pkg/k8s/registry.go

@@ -83,7 +83,7 @@ func DeployMCPRegistry(ctx *pulumi.Context, cluster *providers.ProviderInfo, env
 					Containers: corev1.ContainerArray{
 						&corev1.ContainerArgs{
 							Name:            pulumi.String("mcp-registry"),
-							Image:           pulumi.String("ghcr.io/modelcontextprotocol/registry:latest"),
+							Image:           pulumi.String("ghcr.io/modelcontextprotocol/registry:main"),
 							ImagePullPolicy: pulumi.String("Always"),
 							Ports: corev1.ContainerPortArray{
 								&corev1.ContainerPortArgs{