Repository: storybook
Issue: Webpack v5 Upgrade - `start-storybook` works but `build-storybook` fails
Labels: bug,configuration babel / webpack,has workaround,builder-webpack5

**Describe the bug**
I recently upgrade my project to Webpack v5. The `start-storybook` command works just fine, but when I run `build-storybook`, I get the following error:

```
info @storybook/react v6.1.11
info
info => Cleaning outputDir C:\Dev\bkp-client\storybook-static
info => Building manager..
info => Loading manager config..
info => Loading presets
info => Loading custom babel config
info => Compiling manager..
C:\Dev\bkp-client\node_modules\webpack\lib\javascript\JavascriptModulesPlugin.js:119
                        throw new TypeError(
                        ^

TypeError: The 'compilation' argument must be an instance of Compilation
    at Function.getCompilationHooks (C:\Dev\bkp-client\node_modules\webpack\lib\javascript\JavascriptModulesPlugin.js:119:10)
    at C:\Dev\bkp-client\node_modules\terser-webpack-plugin\dist\index.js:571:67
    at SyncHook.eval [as call] (eval at create (C:\Dev\bkp-client\node_modules\tapable\lib\HookCodeFactory.js:19:10), <anonymous>:87:1)
    at SyncHook.lazyCompileHook (C:\Dev\bkp-client\node_modules\tapable\lib\Hook.js:154:20)
    at C:\Dev\bkp-client\node_modules\@storybook\core\node_modules\webpack\lib\Compiler.js:667:29
    at AsyncSeriesHook.eval [as callAsync] (eval at create (C:\Dev\bkp-client\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:6:1)
    at AsyncSeriesHook.lazyCompileHook (C:\Dev\bkp-client\node_modules\tapable\lib\Hook.js:154:20)
    at Compiler.compile (C:\Dev\bkp-client\node_modules\@storybook\core\node_modules\webpack\lib\Compiler.js:662:28)
    at C:\Dev\bkp-client\node_modules\@storybook\core\node_modules\webpack\lib\Compiler.js:321:11
    at Array.<anonymous> (C:\Dev\bkp-client\node_modules\@storybook\core\node_modules\webpack\lib\Compiler.js:534:20)
    at Storage.finished (C:\Dev\bkp-client\node_modules\@storybook\core\node_modules\enhanced-resolve\lib\CachedInputFileSystem.js:55:16)
    at C:\Dev\bkp-client\node_modules\@storybook\core\node_modules\enhanced-resolve\lib\CachedInputFileSystem.js:91:9
    at callback (C:\Dev\bkp-client\node_modules\graceful-fs\polyfills.js:295:20)
    at FSReqCallback.oncomplete (fs.js:183:21)
npm ERR! code 1
```
I saw a similar error with the `html-webpack-plugin`, so it may just be that Storybook 6 is incompatable with Webpack 5, but it's strange that `start-storybook` works while `build-storybook` fails.

**To Reproduce**
Use Storybook with Webpack v5.

**Expected behavior**
I would expect that a working `start-storybook` implies that `build-storybook` works as well. It's a bit confusing to have my normal Storybook workflow work perfectly but the build tools are unable to build. How does `start-storybook` actually work if it's not building the Storybook?

**System**
Environment Info:

  System:
    OS: Windows 10 10.0.18363
    CPU: (8) x64 Intel(R) Core(TM) i7-8565U CPU @ 1.80GHz
  Binaries:
    Node: 14.15.1 - C:\Program Files\nodejs\node.EXE
    npm: 7.5.3 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Chrome: 88.0.4324.150
    Edge: Spartan (44.18362.449.0)
  npmPackages:
    @storybook/addon-actions: ^6.1.11 => 6.1.11
    @storybook/addon-links: ^6.1.11 => 6.1.11
    @storybook/addons: ^6.1.11 => 6.1.11
    @storybook/preset-typescript: ^3.0.0 => 3.0.0
    @storybook/react: ^6.1.11 => 6.1.11
    @storybook/storybook-deployer: ^2.8.7 => 2.8.7