build(deps): bump kamal from 2.7.0 to 2.8.1

Bumps [kamal](https://github.com/basecamp/kamal) from 2.7.0 to 2.8.1.
- [Release notes](https://github.com/basecamp/kamal/releases)
- [Commits](basecamp/kamal@v2.7.0...v2.8.1)

---
updated-dependencies:
- dependency-name: kamal
  dependency-version: 2.8.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Gemfile.lock

@@ -135,7 +135,7 @@ GEM
       rdoc (>= 4.0.0)
       reline (>= 0.4.2)
     json (2.15.1)
-    kamal (2.7.0)
+    kamal (2.8.1)
       activesupport (>= 7.0)
       base64 (~> 0.2)
       bcrypt_pbkdf (~> 1.0)