Bump devise-i18n from 1.12.1 to 1.15.0

Bumps [devise-i18n](https://github.com/devise-i18n/devise-i18n) from 1.12.1 to 1.15.0.
- [Release notes](https://github.com/devise-i18n/devise-i18n/releases)
- [Changelog](https://github.com/devise-i18n/devise-i18n/blob/master/CHANGELOG.md)
- [Commits](https://github.com/devise-i18n/devise-i18n/compare/v1.12.1...v1.15.0)

---
updated-dependencies:
- dependency-name: devise-i18n
  dependency-version: 1.15.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Gemfile.lock

@@ -275,8 +275,9 @@ GEM
       warden (~> 1.2.3)
     devise-encryptable (0.2.0)
       devise (>= 2.1.0)
-    devise-i18n (1.12.1)
+    devise-i18n (1.15.0)
       devise (>= 4.9.0)
+      rails-i18n
     devise-token_authenticatable (1.1.0)
       devise (>= 4.0.0, < 5.0.0)
     diff-lcs (1.6.2)