Bump puma from 3.12.2 to 4.3.12 (#8)

Bumps [puma](https://github.com/puma/puma) from 3.12.2 to 4.3.12.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](puma/puma@v3.12.2...v4.3.12)

---
updated-dependencies:
- dependency-name: puma
  dependency-type: direct:production
...

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

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

Author: dependabot[bot]

Gemfile.lock

@@ -3,10 +3,12 @@ GEM
   specs:
     coderay (1.1.2)
     method_source (0.9.2)
+    nio4r (2.5.8)
     pry (0.12.2)
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
-    puma (3.12.2)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     slim (4.0.1)
       temple (>= 0.7.6, < 0.9)
       tilt (>= 2.0.6, < 2.1)