build(deps): update vanilla/nbbc requirement from 2.4.0 to 2.6.0 (#1827)

Updates the requirements on [vanilla/nbbc](https://github.com/vanilla/nbbc) to permit the latest version.
- [Release notes](https://github.com/vanilla/nbbc/releases)
- [Changelog](https://github.com/vanilla/nbbc/blob/master/CHANGELOG)
- [Commits](vanilla/nbbc@v2.4.0...v2.6.0)

---
updated-dependencies:
- dependency-name: vanilla/nbbc
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

composer.json

@@ -15,7 +15,7 @@
 		"php-di/php-di": "7.0.6",
 		"phpmailer/phpmailer": "6.9.1",
 		"team-reflex/discord-php": "7.3.5",
-		"vanilla/nbbc": "2.4.0"
+		"vanilla/nbbc": "2.6.0"
 	},
 	"autoload": {
 		"psr-4": {