Release 0.39: Create RC release (#7983)

# Description

Creating RC release for 0.39

## Type of change

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Fixes: #issue_number

## Contributor checklist
Please verify that the PR meets the following requirements, where
applicable:

- [ ] An overview of proposed schema changes is included in a linked
GitHub issue. -- N/A
- [ ] A design document PR is created in the [design-notes
repository](https://github.com/radius-project/design-notes/), if new
APIs are being introduced. -- N/A
- [ ] If applicable, design document has been reviewed and approved by
Radius maintainers/approvers. -- N/A
- [ ] A PR for the [samples
repository](https://github.com/radius-project/samples) is created, if
existing samples are affected by the changes in this PR. -- N/A
- [ ] A PR for the [documentation
repository](https://github.com/radius-project/docs) is created, if the
changes in this PR affect the documentation or any user facing updates
are made. -- N/A
- [ ] A PR for the [recipes
repository](https://github.com/radius-project/recipes) is created, if
existing recipes are affected by the changes in this PR. -- N/A

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

versions.yaml

@@ -1,4 +1,6 @@
 supported:
+  - channel: '0.39'
+    version: 'v0.39.0-rc1'
   - channel: '0.38'
     version: 'v0.38.0'
 deprecated: