test: fix test for npm 8

Author: UziTech

test/prepare.test.js

@@ -137,7 +137,7 @@ test('Use default indentation and newline if it cannot be detected', async (t) =
   );
 
   // Verify package.json has been updated
-  t.is(await readFile(packagePath, 'utf-8'), `{\n  "name": "package-name",\n  "version": "1.0.0"\n}\n`);
+  t.is(await readFile(packagePath, 'utf-8'), `{"name":"package-name","version":"1.0.0"}`);
 
   // Verify the logger has been called with the version updated
   t.is(t.context.log.args[0][0], 'Write version 1.0.0 to package.json');