cli/webpack: replace depreacted hash with fullhash

Signed-off-by: Johan Haals <johan.haals@gmail.com>

.changeset/thirty-gorillas-pull.md

@@ -0,0 +1,5 @@
+---
+'@backstage/cli': patch
+---
+
+Remove webpack deprecation message when running build.

packages/cli/src/lib/bundler/config.ts

@@ -209,7 +209,7 @@ export async function createConfig(
     output: {
       path: paths.targetDist,
       publicPath: validBaseUrl.pathname,
-      filename: isDev ? '[name].js' : 'static/[name].[hash:8].js',
+      filename: isDev ? '[name].js' : 'static/[name].[fullhash:8].js',
       chunkFilename: isDev
         ? '[name].chunk.js'
         : 'static/[name].[chunkhash:8].chunk.js',