Enable dependabot for /deploy and pin Go version to 1.24 (#697)

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## Motivation and Context
<!-- Why is this change needed? What problem does it solve? -->
There was feedback that other projects wanting to use the registry
package have to upgrade to 1.25 (because of how Go works). In the
registry itself we are not relying on 1.25 features so this PR reverts
us back to 1.24 until 1.25 becomes better adopted and we can safely move
to it.

Also realised we were not keeping our dependencies for our deploy/infra
code up to date with Dependabot so this fixes that too.

## How Has This Been Tested?
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tested? -->

## Breaking Changes
<!-- Will users need to update their code or configurations? -->

## 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)
- [ ] 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/go.mod

@@ -1,8 +1,6 @@
 module github.com/modelcontextprotocol/registry/deploy/infra
 
-go 1.23.0
-
-toolchain go1.24.1
+go 1.24.6
 
 require (
 	github.com/pulumi/pulumi-gcp/sdk/v8 v8.39.0