Update @hypothesis/frontend-shared to v4.0.0

This required a couple of changes to adapt to the removal of the
CommonJS build. Some modules from the pattern library web app triggered
a Babel warning about top-level `this`. I copied across the workaround
from `rollup.config.js` in the @hypothesis/frontend-shared library.

dev-server/ui-playground/components/ButtonPatterns.js

@@ -6,7 +6,7 @@ import {
 
 // TODO: Update after https://github.com/hypothesis/frontend-shared/issues/179
 // is resolved
-import Library from '@hypothesis/frontend-shared/lib-cjs/pattern-library/components/Library';
+import Library from '@hypothesis/frontend-shared/lib/pattern-library/components/Library';
 
 export default function ButtonPatterns() {
   return (

dev-server/ui-playground/index.js

-import { startApp } from '@hypothesis/frontend-shared/lib-cjs/pattern-library';
+import { startApp } from '@hypothesis/frontend-shared/lib/pattern-library';
 import ButtonPatterns from './components/ButtonPatterns';
 
 import sidebarIcons from '../../src/sidebar/icons';

package.json

@@ -13,7 +13,7 @@
     "@babel/preset-env": "^7.1.6",
     "@babel/preset-react": "^7.0.0",
     "@hypothesis/frontend-build": "^1.0.1",
-    "@hypothesis/frontend-shared": "3.14.0",
+    "@hypothesis/frontend-shared": "^4.0.0",
     "@octokit/rest": "^18.0.0",
     "@rollup/plugin-alias": "^3.1.2",
     "@rollup/plugin-babel": "^5.3.0",

rollup.config.mjs

@@ -38,6 +38,12 @@ function bundleConfig({ name, entry, format = 'es' }) {
 
     treeshake: isProd,
 
+    // Suppress a warning (https://rollupjs.org/guide/en/#error-this-is-undefined)
+    // due to https://github.com/babel/babel/issues/9149.
+    //
+    // Any code string other than "undefined" which evaluates to `undefined` will work here.
+    context: 'void(0)',
+
     plugins: [
       alias({
         entries: [

yarn.lock

@@ -1131,10 +1131,10 @@
     fancy-log "^1.3.3"
     glob "^7.2.0"
 
-"@hypothesis/frontend-shared@3.14.0":
-  version "3.14.0"
-  resolved "https://registry.yarnpkg.com/@hypothesis/frontend-shared/-/frontend-shared-3.14.0.tgz#0dc3f1f0df22841b19428840ea1318fcf3c8b6d1"
-  integrity sha512-vkgVGruGJyku8pVegV1/mxyyQjyeg1xLZNxFHaGkqZ9Ho5GYHgkmqv40Z6tfZbSXpcUpAGlHRVy5+fasgwhhOA==
+"@hypothesis/frontend-shared@^4.0.0":
+  version "4.0.0"
+  resolved "https://registry.yarnpkg.com/@hypothesis/frontend-shared/-/frontend-shared-4.0.0.tgz#dbd136e7636e5eab37aa1b7690aacca8ce2a7f5a"
+  integrity sha512-zg6NH+te8ghqP6nUeC3fqIr6i0Er1njs7ySwFaZq4NIlZJTN+4ImK/DSMJF3aE8AWL0UwQpTfpJQKeaJuR51OA==
   dependencies:
     normalize.css "^8.0.1"