Bump kamal from 2.6.1 to 2.8.1

Bumps [kamal](https://github.com/basecamp/kamal) from 2.6.1 to 2.8.1.
- [Release notes](https://github.com/basecamp/kamal/releases)
- [Commits](basecamp/kamal@v2.6.1...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

@@ -78,7 +78,7 @@ GEM
     base64 (0.3.0)
     bcrypt_pbkdf (1.1.1)
     benchmark (0.4.1)
-    bigdecimal (3.2.1)
+    bigdecimal (3.3.1)
     bindex (0.8.1)
     bootsnap (1.18.6)
       msgpack (~> 1.2)
@@ -95,7 +95,7 @@ GEM
       regexp_parser (>= 1.5, < 3.0)
       xpath (~> 3.2)
     concurrent-ruby (1.3.5)
-    connection_pool (2.5.3)
+    connection_pool (2.5.4)
     crass (1.0.6)
     date (3.4.1)
     debug (1.10.0)
@@ -129,7 +129,7 @@ GEM
       actionview (>= 5.0.0)
       activesupport (>= 5.0.0)
     json (2.12.2)
-    kamal (2.6.1)
+    kamal (2.8.1)
       activesupport (>= 7.0)
       base64 (~> 0.2)
       bcrypt_pbkdf (~> 1.0)
@@ -156,7 +156,7 @@ GEM
     marcel (1.0.4)
     matrix (0.4.2)
     mini_mime (1.1.5)
-    minitest (5.25.5)
+    minitest (5.26.0)
     msgpack (1.8.0)
     net-imap (0.5.8)
       date
@@ -187,7 +187,7 @@ GEM
       racc (~> 1.4)
     nokogiri (1.18.8-x86_64-linux-musl)
       racc (~> 1.4)
-    ostruct (0.6.1)
+    ostruct (0.6.3)
     parallel (1.27.0)
     parser (3.3.8.0)
       ast (~> 2.4.1)
@@ -356,7 +356,7 @@ GEM
     unicode-display_width (3.1.4)
       unicode-emoji (~> 4.0, >= 4.0.4)
     unicode-emoji (4.0.4)
-    uri (1.0.3)
+    uri (1.0.4)
     useragent (0.16.11)
     web-console (4.2.1)
       actionview (>= 6.0.0)