Bump webmock from 3.20.0 to 3.22.0 in /slack-unfurling-esa

Bumps [webmock](https://github.com/bblimke/webmock) from 3.20.0 to 3.22.0.
- [Changelog](https://github.com/bblimke/webmock/blob/master/CHANGELOG.md)
- [Commits](bblimke/webmock@v3.20.0...v3.22.0)

---
updated-dependencies:
- dependency-name: webmock
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

slack-unfurling-esa/Gemfile.lock

@@ -5,7 +5,7 @@ GEM
       public_suffix (>= 2.0.2, < 6.0)
     base64 (0.1.1)
     bigdecimal (3.1.6)
-    crack (0.4.6)
+    crack (1.0.0)
       bigdecimal
       rexml
     esa (2.1.0)
@@ -34,7 +34,7 @@ GEM
     public_suffix (5.0.4)
     rexml (3.2.6)
     ruby2_keywords (0.0.5)
-    webmock (3.20.0)
+    webmock (3.22.0)
       addressable (>= 2.8.0)
       crack (>= 0.3.2)
       hashdiff (>= 0.4.0, < 2.0.0)