feat: bump minimum node version to 16 and add tests (#86)

BREAKING CHANGE: Minimum node version is now 16

src/sha.ts

@@ -1,16 +1,13 @@
 import * as fs from 'fs-extra';
 import * as crypto from 'crypto';
+import { pipeline } from 'stream/promises';
+
 import { d } from './debug';
 
 export const sha = async (filePath: string) => {
   d('hashing', filePath);
   const hash = crypto.createHash('sha256');
   hash.setEncoding('hex');
-  const fileStream = fs.createReadStream(filePath);
-  fileStream.pipe(hash);
-  await new Promise((resolve, reject) => {
-    fileStream.on('end', () => resolve());
-    fileStream.on('error', (err) => reject(err));
-  });
+  await pipeline(fs.createReadStream(filePath), hash);
   return hash.read();
 };