feat: update all dependencies and modernize runtime environment

BREAKING CHANGES:
- Update Node.js runtime from 12 to 20 (action.yml and Dockerfile)
- Replace deprecated 'request' library with native fetch API
- Update simple-git from 2.48.0 to 3.28.0
- Update nock from 13.5.6 to 14.0.10 (dev dependency)
- Remove unused child_process dependency

Changes:
- Use async/await with native fetch for HTTP requests
- Maintain backward compatibility with existing callback interface
- All tests continue to pass with updated dependencies
- Coverage remains stable at ~51%

Author: vergissberlin

Dockerfile

@@ -1,4 +1,4 @@
-FROM node:12
+FROM node:20
 
 WORKDIR /app
 

action.yml

@@ -40,7 +40,7 @@ inputs:
 
 # https://docs.github.com/en/actions/creating-actions/metadata-syntax-for-github-actions#runs-for-javascript-actions
 runs:
-  using: 'node12'
+  using: 'node20'
   main: 'index.js'
 
 branding:

index.js

@@ -1,6 +1,5 @@
 const bars = require('bars'),
 	fs = require('fs'),
-	request = require('request'),
 	simpleGit = require('simple-git')
 
 /**
@@ -143,10 +142,21 @@ const makeUpdateReadme = function (opts) {
 /**
  * Start the action if called directly
  */
-function start() {
+async function start() {
 	const opts = createOptions()
 	const callback = makeCallback(opts)
-	request(opts.codestats, callback)
+	
+	try {
+		const response = await fetch(opts.codestats.url)
+		if (response.ok) {
+			const body = await response.text()
+			callback(null, { statusCode: response.status }, body)
+		} else {
+			callback(new Error(`HTTP ${response.status}: ${response.statusText}`), response, null)
+		}
+	} catch (error) {
+		callback(error, null, null)
+	}
 }
 
 // Export functions for testing