Release 0.25: Create rc release (#6260)

# Description

Creating RC release for 0.25.0

## Type of change

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Fixes: #issue_number

## Auto-generated summary

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### <samp>🤖 Generated by Copilot at cfa10f5</samp>

### Summary
:sparkles::bookmark::memo:

<!--
1. :sparkles: - This emoji represents the addition of a new feature or
enhancement, which in this case is the new entry for radius 0.25 in the
versions.yaml file.
2. :bookmark: - This emoji represents the creation of a new release or
tag, which in this case is the release candidate for radius 0.25.
3. :memo: - This emoji represents the documentation or metadata update,
which in this case is the update to the versions.yaml file with the
latest release information.
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Update `versions.yaml` with latest release candidate for radius 0.25.
This file tracks the available channels and versions of radius releases.

> _`versions.yaml` changed_
> _new release candidate set_
> _autumn of radius_

### Walkthrough
* Add a new entry for radius 0.25 release candidate
([link](https://github.com/radius-project/radius/pull/6260/files?diff=unified&w=0#diff-1c4cd801df522f4a92edbfb0fea95364ed074a391ea47c284ddc078f512f7b6aR2-R3))

Co-authored-by: karishma-chawla <[email protected]>

versions.yaml

@@ -1,4 +1,6 @@
 supported:
+  - channel: '0.25'
+    version: 'v0.25.0-rc1'
   - channel: '0.24'
     version: 'v0.24.0'
 deprecated: