fix(ruby-version): skipped installation of existing ruby versions

Author: travi

src/ruby-version-test.js

@@ -23,7 +23,7 @@ suite('ruby-version', () => {
     await scaffoldRubyVersion(projectRoot);
 
     assert.calledWith(fsPromises.writeFile, `${projectRoot}/.ruby-version`, '2.6.3');
-    assert.calledWith(execa.default, 'rbenv', ['install']);
+    assert.calledWith(execa.default, 'rbenv', ['install', '--skip-existing']);
     assert.isTrue(execa.default.calledAfter(fsPromises.writeFile));
   });
 });

src/ruby-version.js

@@ -4,5 +4,5 @@ import execa from '../thirdparty-wrappers/execa';
 export default async function (projectRoot) {
   await promises.writeFile(`${projectRoot}/.ruby-version`, '2.6.3');
 
-  await execa('rbenv', ['install']);
+  await execa('rbenv', ['install', '--skip-existing']);
 }