Merge #1016: ci: Use bundler 2.4.22

0c10f28 ci: Use bundler 2.4.22 (Ava Chow)

Pull request description:

  The last version of bundle to support ruby 2.7.4 is 2.4.22. Should fix the current CI failure.

ACKs for top commit:
  laanwj:
    ACK 0c10f28

Tree-SHA512: a68213e43ab69e6119b0bf7bcdecec2a7f99baf6929ea5c8bf3e6ad1f4d6c911a13137b185d12c979bb8347c54d945b44bd442491249e99af01516eaea4fdf6d

.cirrus.yml

@@ -9,7 +9,7 @@ env:
 task:
   name: Bundler build
 
-  bootstrap_script: gem install bundler
+  bootstrap_script: gem install bundler -v 2.4.22
   bundler_cache:
     folder: /usr/local/bundle
     fingerprint_script: