Bump sinatra-activerecord from 2.0.27 to 2.0.28 (#186)

Bumps [sinatra-activerecord](https://github.com/janko-m/sinatra-activerecord) from 2.0.27 to 2.0.28.
- [Changelog](https://github.com/sinatra-activerecord/sinatra-activerecord/blob/master/CHANGELOG.md)
- [Commits](https://github.com/janko-m/sinatra-activerecord/commits)

---
updated-dependencies:
- dependency-name: sinatra-activerecord
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Gemfile.lock

@@ -139,7 +139,7 @@ GEM
     marcel (1.0.4)
     mini_mime (1.1.5)
     mini_portile2 (2.8.7)
-    minitest (5.25.1)
+    minitest (5.25.2)
     mustermann (3.0.3)
       ruby2_keywords (~> 0.0.1)
     net-imap (0.5.0)
@@ -258,7 +258,7 @@ GEM
       rubocop (~> 1.61)
     ruby-progressbar (1.13.0)
     ruby2_keywords (0.0.5)
-    securerandom (0.3.1)
+    securerandom (0.3.2)
     simplecov (0.22.0)
       docile (~> 1.1)
       simplecov-html (~> 0.11)
@@ -272,7 +272,7 @@ GEM
       rack-protection (= 4.1.1)
       rack-session (>= 2.0.0, < 3)
       tilt (~> 2.0)
-    sinatra-activerecord (2.0.27)
+    sinatra-activerecord (2.0.28)
       activerecord (>= 4.1)
       sinatra (>= 1.0)
     sqlite3 (1.7.3)