fix: Remove 'v' prefix from release VERSION

Since the command is only executed when the GITHUB_REF has a specific
prefix, I think it's fine to strip exactly that prefix.

Performing the change in the release workflow allows the release.sh script
to keep treating the VERSION as an opaque string.

.github/workflows/build_release.yml

@@ -32,7 +32,7 @@ jobs:
 
       - name: Set VERSION if tagged build
         if: startsWith(github.event.ref, 'refs/tags/v')
-        run: echo "VERSION=${GITHUB_REF#refs/*/}" >> $GITHUB_ENV
+        run: echo "VERSION=${GITHUB_REF#refs/tags/v}" >> $GITHUB_ENV
 
       - name: Build the release zip packages
         if: github.event_name != 'pull_request'