fix: update detection of changelog links (#573)

The Node.js `CHANGELOG.md` file was changed so that `_` characters in
links are now escaped.

Refs: nodejs/node#40322

lib/prepare_release.js

@@ -331,7 +331,8 @@ class ReleasePreparation {
     const data = await fs.readFile(mainChangelogPath, 'utf8');
     const arr = data.split('\n');
 
-    const hrefLink = `doc/changelogs/CHANGELOG_V${versionComponents.major}.md`;
+    const major = versionComponents.major;
+    const hrefLink = `doc/changelogs/CHANGELOG\\_V${major}.md`;
     const newRefLink = `<a href="${hrefLink}#${newVersion}">${newVersion}</a>`;
     const lastRefLink = `<a href="${hrefLink}#${lastRef}">${lastRef}</a>`;