docs(openapi): add openapi for search, updated_since, version params (#654)

Updating openapi.yaml to be in sync with latest changes. Funcitonality
for search param introduced back in
https://github.com/modelcontextprotocol/registry/pull/374

## Motivation and Context
<!-- Why is this change needed? What problem does it solve? -->

## How Has This Been Tested?
N/A

## Breaking Changes
N/A

## 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. -->
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [ ] New and existing tests pass locally
- [ ] I have added appropriate error handling
- [x] I have added or updated documentation as needed

---------

Co-authored-by: Radoslav Dimitrov <radoslav@stacklok.com>

docs/reference/api/openapi.yaml

@@ -39,6 +39,28 @@ paths:
           required: false
           schema:
             type: integer
+        - name: search
+          in: query
+          description: Search servers by name (substring match)
+          required: false
+          schema:
+            type: string
+            example: "filesystem"
+        - name: updated_since
+          in: query
+          description: Filter servers updated since timestamp (RFC3339 datetime)
+          required: false
+          schema:
+            type: string
+            format: date-time
+            example: "2025-08-07T13:15:04.280Z"
+        - name: version
+          in: query
+          description: Filter by version ('latest' for latest version, or an exact version like '1.2.3')
+          required: false
+          schema:
+            type: string
+            example: "1.2.3"
       responses:
         '200':
           description: A list of MCP servers