Fix the image tag to strip the v prefix (#726)

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## Motivation and Context
<!-- Why is this change needed? What problem does it solve? -->
We forgot to strip the v prefix when we made the switch to ko so this PR
fixes it.

Once we merge it we'll cut a new release so we can apply this change 👍 

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

## Breaking Changes
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## Types of changes
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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
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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>

.github/workflows/release.yml

@@ -69,8 +69,9 @@ jobs:
         id: build-info
         run: |
           echo "timestamp=$(date -u +%Y-%m-%dT%H:%M:%SZ)" >> $GITHUB_OUTPUT
-          # Extract version from tag (e.g., refs/tags/v1.2.3 -> v1.2.3)
+          # Extract version from tag and strip 'v' prefix (e.g., refs/tags/v1.2.3 -> 1.2.3)
           VERSION="${GITHUB_REF#refs/tags/}"
+          VERSION="${VERSION#v}"
           echo "version=$VERSION" >> $GITHUB_OUTPUT
 
       - name: Build and push with ko