minimum TS is 4.2

Author: SimenB

.github/workflows/nodejs.yml

@@ -58,7 +58,7 @@ jobs:
         run: yarn build
       - name: test typings
         run: yarn test-types
-      - name: verify TypeScript@3.8 compatibility
+      - name: verify TypeScript@4.2 compatibility
         run: yarn verify-old-ts
       - name: verify Yarn PnP compatibility
         run: yarn verify-pnp

scripts/verifyOldTs.js

@@ -29,7 +29,7 @@ const tsConfig = {
 };
 const cwd = tempy.directory();
 
-const tsVersion = '3.8';
+const tsVersion = '4.2';
 
 try {
   fs.writeFileSync(path.join(cwd, '.yarnrc.yml'), 'nodeLinker: node-modules\n');