Bump securerandom from 0.3.2 to 0.4.0 in /gemfile_steep

Bumps [securerandom](https://github.com/ruby/securerandom) from 0.3.2 to 0.4.0.
- [Release notes](https://github.com/ruby/securerandom/releases)
- [Commits](ruby/securerandom@v0.3.2...v0.4.0)

---
updated-dependencies:
- dependency-name: securerandom
  dependency-type: indirect
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

gemfile_steep/Gemfile.lock

@@ -48,7 +48,7 @@ GEM
     rbs-inline (0.10.0)
       prism (>= 0.29, < 1.3)
       rbs (>= 3.5.0)
-    securerandom (0.3.2)
+    securerandom (0.4.0)
     steep (1.9.0.dev.2)
       activesupport (>= 5.1)
       concurrent-ruby (>= 1.1.10)