Replace unsupported flag -s wiht staticDirs

In 6.4 Storybook replaced the --static-dir CLI flag with the staticDirs
field in .storybook/main.js. Note that the CLI directories are relative
to the current working directory, whereas the staticDirs are relative to
the location of main.js.

See #deprecated---static-dir-cli-flag on
https://github.com/storybookjs/storybook/blob/next/MIGRATION.md

.storybook/main.js

@@ -1,6 +1,7 @@
 const TsconfigPathsPlugin = require('tsconfig-paths-webpack-plugin');
 
 module.exports = {
+  staticDirs: ['../src'],
   stories: ['../src/**/*.mdx', '../src/**/*.stories.@(js|jsx|ts|tsx)'],
 
   addons: [

package.json

@@ -20,7 +20,7 @@
     "playwright": "cross-env NODE_ENV=production playwright test",
     "playwright:skipbuild": "cross-env NODE_ENV=production SKIP_BUILD=1 playwright test",
     "playwright:ci": "cross-env NODE_ENV=production playwright test",
-    "storybook": "storybook dev -p 6006 -s ./src",
+    "storybook": "storybook dev -p 6006",
     "make-yaml": "ts-node src/tools/make-yaml.ts",
     "build-storybook": "storybook build"
   },