build(docker): publish short tags for stable releases (#34435)

tools/utils/docker.ts

@@ -32,7 +32,7 @@ export async function bake(
   if (opts.version) {
     console.log(`Using version: ${opts.version.version}`);
     process.env.RENOVATE_VERSION = opts.version.version;
-    if (!opts.version.prerelease) {
+    if (!opts.version.prerelease.length) {
       process.env.RENOVATE_MAJOR_VERSION = `${opts.version.major}`;
       process.env.RENOVATE_MAJOR_MINOR_VERSION = `${opts.version.major}.${opts.version.minor}`;
     }