fix: pre-built binary support for Ubuntu 20.04 (#2728)

## Overview

I think this should fix #2727, I didn't see any docs to see how to
format the version specified for ubuntu

## Checklist

- [x] New and updated code has appropriate documentation
- [x] New and updated code has new and/or updated testing
- [x] Required CI checks are passing
- [x] Visual proof for any user facing features like CLI or
documentation updates
- [x] Linked issues closed with keywords

## Testing

Tested with
[celestia-app_Linux_x86_64.tar.gz](https://github.com/rootulp/celestia-app/releases/download/v1.0.0-rc7/celestia-app_Linux_x86_64.tar.gz)
created on
https://github.com/rootulp/celestia-app/releases/tag/v1.0.0-rc7

OS | Version | Works
--- | --- | ---
Ubuntu | 20.04 | ✅ 
Ubuntu | 23.04 | ✅

---------

Co-authored-by: Rootul Patel <[email protected]>

.github/workflows/ci-release.yml

@@ -70,7 +70,7 @@ jobs:
   # Generate the release with goreleaser to include pre-built binaries
   goreleaser:
     needs: version_bump
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     if: |
       github.event_name == 'workflow_dispatch' ||
       (github.event_name == 'push' && contains(github.ref, 'refs/tags/'))