doc: add .github to CODEOWNERS

Add .github directory to CODEOWNERS file.

PR-URL: #20733
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Yuta Hiroto <hello@hiroppy.me>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

.github/CODEOWNERS

@@ -78,6 +78,7 @@ android-configure @nodejs/build
 /src/*.d @nodejs/diagnostics @nodejs/platform-smartos @nodejs/platform-freebsd @nodejs/platform-macos @nodejs/dtrace-mdb
 /src/node.stp @nodejs/diagnostics
 
+/.github/ @nodejs/tsc
 CODE_OF_CONDUCT.md @nodejs/tsc
 COLLABORATOR_GUIDE.md @nodejs/tsc
 CONTRIBUTING.md @nodejs/tsc