Bump excon from 1.2.8 to 1.3.0 in the ruby-dependencies group (heroku#1639)

Bumps the ruby-dependencies group with 1 update: [excon](https://github.com/excon/excon).


Updates `excon` from 1.2.8 to 1.3.0
- [Changelog](https://github.com/excon/excon/blob/master/changelog.txt)
- [Commits](excon/excon@v1.2.8...v1.3.0)

---
updated-dependencies:
- dependency-name: excon
  dependency-version: 1.3.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: ruby-dependencies
...

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

Author: dependabot[bot]

Gemfile.lock

@@ -6,7 +6,7 @@ GEM
     connection_pool (2.5.3)
     diff-lcs (1.6.2)
     erubis (2.7.0)
-    excon (1.2.8)
+    excon (1.3.0)
       logger
     heroics (0.1.3)
       base64