[Release|CI/CD] Update runtime artefact's name before upload to a GitHub draft release (#7814)

This PR is an improvement of the Create Release Draft workflow. Due to
the switch to the direct use of `gh` to upload artefacts to the release
draft, behaviour of it has slightly changed. `gh` renames only a display
name of the file but not the file it self.
This pr adds renaming before the upload so that displayed name of the
attachment and the file itself have the same name that includes
`spec_version` in it.

Closes: https://github.com/paritytech/release-engineering/issues/250

cc: @BulatSaif

.github/workflows/release-30_publish_release_draft.yml

@@ -176,9 +176,11 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ steps.generate_write_token.outputs.token }}
         run: |
+          VERSIONED_ASSET="${{ matrix.chain }}_runtime-v${{ env.SPEC }}.compact.compressed.wasm"
+          mv "${{ env.ASSET }}" "$VERSIONED_ASSET"
+
           gh release upload ${{ needs.validate-inputs.outputs.release_tag }} \
-            --repo paritytech/polkadot-sdk \
-            '${{ env.ASSET }}#${{ matrix.chain }}_runtime-v${{ env.SPEC }}.compact.compressed.wasm'
+            --repo paritytech/polkadot-sdk "$VERSIONED_ASSET"
 
   publish-release-artifacts:
     needs: [ validate-inputs, publish-release-draft ]