fix(typescript): bump TypeScript version (#818)

* chore(typescript): bump TypeScript version

* Revert "feat(typescript): error when no tsconfig and no rootDir (#794)"

This reverts commit cbfd779.

packages/typescript/package.json

@@ -61,7 +61,7 @@
     "@types/node": "^10.0.0",
     "buble": "^0.20.0",
     "rollup": "^2.14.0",
-    "typescript": "^4.1.2"
+    "typescript": "^4.2.2"
   },
   "types": "types/index.d.ts"
 }

packages/typescript/src/preflight.ts

@@ -17,8 +17,6 @@ ${pluginName}: Rollup requires that TypeScript produces ES Modules. Unfortunatel
  "module" other than "esnext". Unless you know what you're doing, please change "module" to "esnext"
  in the target tsconfig.json file or plugin options.`.replace(/\n/g, '');
 
-const rootDirErrorMessage = `${pluginName}: The "rootDir" or "rootDirs" option is required when the "tsconfig" option is not specified and "declaration" is "true".`;
-
 const tsLibErrorMessage = `${pluginName}: Could not find module 'tslib', which is required by this plugin. Is it installed?`;
 
 let undef;
@@ -30,11 +28,6 @@ export const preflight = ({ config, context, rollupOptions, tslib }: PreflightOp
     context.warn(moduleErrorMessage);
   }
 
-  const { options } = config;
-  if (options.declaration && !options.configFilePath && !options.rootDir && !options.rootDirs) {
-    context.error(rootDirErrorMessage);
-  }
-
   if (!rollupOptions.preserveModules && tslib === null) {
     context.error(tsLibErrorMessage);
   }

packages/typescript/test/test.js

@@ -1020,11 +1020,7 @@ test.serial('picks up on newly included typescript files in watch mode', async (
   t.true(usage, 'should contain usage');
 });
 
-// TODO: upgrade TypeScript when there is a release containing the fix for this issue
-// https://github.com/microsoft/TypeScript/pull/41811. Then enable this test
-// More details at https://github.com/rollup/plugins/issues/287. This fails with the message:
-// Unexpected token (Note that you need plugins to import files that are not JavaScript)
-test.serial.skip('works when code is in src directory', async (t) => {
+test.serial('works when code is in src directory', async (t) => {
   const bundle = await rollup({
     input: 'fixtures/src-dir/src/index.ts',
     output: [