fix fetch setup issue

[msu-copilot]

When I run npm run server, I encountered the error below. I want to fix this by installing a fetch library and have the app to use it.

======
npm run server

[email protected] server
node app.js

/Users/msu/github-app-js-sample/node_modules/@octokit/request/dist-node/index.js:69
throw new Error(
^

Error: fetch is not set. Please pass a fetch implementation as new Octokit({ request: { fetch }}). Learn more at https://github.com/octokit/octokit.js/#fetch-missing
at fetchWrapper (/Users/msu/github-app-js-sample/node_modules/@octokit/request/dist-node/index.js:69:11)
at request2 (/Users/msu/github-app-js-sample/node_modules/@octokit/request/dist-node/index.js:192:14)
at hook (/Users/msu/github-app-js-sample/node_modules/@octokit/auth-app/dist-node/index.js:364:24)
at async requestWithGraphqlErrorHandling (/Users/msu/github-app-js-sample/node_modules/@octokit/plugin-retry/dist-node/index.js:71:20)
at async Job.doExecute (/Users/msu/github-app-js-sample/node_modules/bottleneck/light.js:405:18)

======

[carturoch]

👋 Hi @msu-copilot! Thank you so much for taking interest in our GitHub App sample for Javascript!

I wasn't able to reproduce this error when running npm run server, on main, in the following environment:

OS: Ubuntu 20.04.6 LTS
Node: v20.11.0
NPM: 10.2.4

Could you verify that the values on your .env file are accurate?

Because this is a "sample", the errors from having an incorrect path to the private key or an invalid APP_ID, are not very informative 😞. I'd recommend revisiting the setup instructions.

Is there something else that you think I could be missing here, that could result in the error you're seeing?

[msu-copilot]

Hi @carturoch , thank you for your response. I discovered the issue was due to the outdated Node version I was using. The problem was resolved after I upgraded from v16 to v20. Therefore, in this PR, I've only updated the Node version in the Readme.

[carturoch]

Thank you! ✨