Upgrade Storybook from 6.4.14 to 6.4.18

Author: iOvergaard

.eslintignore

@@ -1 +1,2 @@
 node_modules/
+.eslintrc.js

.eslintrc.js

@@ -10,6 +10,7 @@ module.exports = {
     'plugin:@typescript-eslint/recommended',
     'plugin:lit/recommended',
     'plugin:lit-a11y/recommended',
+    'plugin:storybook/recommended',
   ],
   rules: {
     // disable the rule for all files

.storybook/main.js

@@ -27,6 +27,7 @@ module.exports = {
       config.optimizeDeps.include.push('lit/directives/style-map.js');
       config.optimizeDeps.include.push('lit/directives/if-defined.js');
       config.optimizeDeps.include.push('lit/directives/unsafe-html.js');
+      config.optimizeDeps.include.push('element-internals-polyfill');
     }
 
     return config;