Remove Leiningen from CircleCI build

Author: danielcompton

.circleci/config.yml

@@ -4,7 +4,7 @@ version: 2.1
 default: &default-steps
   steps:
     - checkout
-    - run: apt-get update && apt-get install make leiningen=2.8.1-6 -y
+    - run: apt-get update && apt-get install make
     - run: make elpa
     - run: emacs --version
     - run: make test