Add Emacs 27 to the CI matrix

Author: bbatsov

.circleci/config.yml

@@ -21,6 +21,12 @@ jobs:
         entrypoint: bash
     <<: *default-steps
 
+  test-emacs-27:
+    docker:
+      - image: silex/emacs:27-ci-cask
+        entrypoint: bash
+    <<: *default-steps
+
   test-emacs-master:
     docker:
       - image: silex/emacs:master-ci-cask
@@ -33,4 +39,5 @@ workflows:
     jobs:
       - test-emacs-25
       - test-emacs-26
+      - test-emacs-27
       - test-emacs-master