Bump better_errors from 2.5.0 to 2.5.1 (mastodon#10050)

Bumps [better_errors](https://github.com/BetterErrors/better_errors) from 2.5.0 to 2.5.1.
- [Release notes](https://github.com/BetterErrors/better_errors/releases)
- [Changelog](https://github.com/BetterErrors/better_errors/blob/master/CHANGELOG.md)
- [Commits](BetterErrors/better_errors@v2.5.0...v2.5.1)

Signed-off-by: dependabot[bot] <support@dependabot.com>

Gemfile.lock

@@ -92,7 +92,7 @@ GEM
     aws-sigv4 (1.0.3)
     bcrypt (3.1.12)
     benchmark-ips (2.7.2)
-    better_errors (2.5.0)
+    better_errors (2.5.1)
       coderay (>= 1.0.0)
       erubi (>= 1.0.0)
       rack (>= 0.9.0)