Bump net-smtp from 0.4.0.1 to 0.5.0

Bumps [net-smtp](https://github.com/ruby/net-smtp) from 0.4.0.1 to 0.5.0.
- [Release notes](https://github.com/ruby/net-smtp/releases)
- [Changelog](https://github.com/ruby/net-smtp/blob/master/NEWS.md)
- [Commits](ruby/net-smtp@v0.4.0.1...v0.5.0)

---
updated-dependencies:
- dependency-name: net-smtp
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Gemfile.lock

@@ -37,7 +37,7 @@ GEM
     mutex_m (0.2.0)
     net-protocol (0.2.2)
       timeout
-    net-smtp (0.4.0.1)
+    net-smtp (0.5.0)
       net-protocol
     nkf (0.2.0)
     parallel (1.24.0)