Bump platform-api from 3.8.0 to 3.9.0

Bumps [platform-api](https://github.com/heroku/platform-api) from 3.8.0 to 3.9.0.
- [Changelog](https://github.com/heroku/platform-api/blob/main/CHANGELOG.md)
- [Commits](https://github.com/heroku/platform-api/compare/v3.8.0...v3.9.0)

---
updated-dependencies:
- dependency-name: platform-api
  dependency-version: 3.9.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Gemfile.lock

@@ -277,7 +277,7 @@ GEM
     erb (6.0.1)
     erubi (1.13.1)
     erubis (2.7.0)
-    excon (1.2.5)
+    excon (1.3.2)
       logger
     execjs (2.10.0)
     factory_bot (6.5.5)
@@ -446,7 +446,7 @@ GEM
       prism (~> 1.5)
     moneta (1.0.0)
     msgpack (1.8.0)
-    multi_json (1.15.0)
+    multi_json (1.19.1)
     multi_xml (0.8.1)
       bigdecimal (>= 3.1, < 5)
     net-http (0.9.1)
@@ -494,7 +494,7 @@ GEM
       capybara (>= 3)
     pg (1.6.3)
     pg (1.6.3-x86_64-linux)
-    platform-api (3.8.0)
+    platform-api (3.9.0)
       heroics (~> 0.1.1)
       moneta (~> 1.0.0)
       rate_throttle_client (~> 0.1.0)