Bump bcrypt from 3.1.13 to 3.1.15 (#14402)

Bumps [bcrypt](https://github.com/codahale/bcrypt-ruby) from 3.1.13 to 3.1.15.
- [Release notes](https://github.com/codahale/bcrypt-ruby/releases)
- [Changelog](https://github.com/codahale/bcrypt-ruby/blob/master/CHANGELOG)
- [Commits](https://github.com/codahale/bcrypt-ruby/compare/v3.1.13...v3.1.15)

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

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

Gemfile.lock

@@ -107,7 +107,7 @@ GEM
       aws-sigv4 (~> 1.1)
     aws-sigv4 (1.2.1)
       aws-eventstream (~> 1, >= 1.0.2)
-    bcrypt (3.1.13)
+    bcrypt (3.1.15)
     better_errors (2.7.1)
       coderay (>= 1.0.0)
       erubi (>= 1.0.0)