docs(core): fix deployment docs example code (#23289)

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## Current Behavior

Using example code directly will result in an error because a
`PackageJson` object cannot be parsed to the `writeFileSync` function.

## Expected Behavior
<!-- This is the behavior we should expect with the changes in this PR
-->

Replace the `writeFileSync` fn with the `writeJsonFile` fn from
'@nx/devkit'

Author: tears330

docs/shared/recipes/ci-deployment.md

@@ -97,6 +97,7 @@ const {
   createProjectGraphAsync,
   readCachedProjectGraph,
   detectPackageManager,
+  writeJsonFile,
 } = require('@nx/devkit');
 const {
   createLockFile,
@@ -128,7 +129,7 @@ async function main() {
 
   const lockFileName = getLockFileName(pm);
 
-  writeFileSync(`${outputDir}/package.json`, packageJson);
+  writeJsonFile(`${outputDir}/package.json`, packageJson);
   writeFileSync(`${outputDir}/${lockFileName}`, lockFile, {
     encoding: 'utf8',
   });