add nightly to CI

Author: IanButterworth

.github/workflows/ci.yml

@@ -22,7 +22,7 @@ jobs:
           - '1.6'
           - '1'
           - '^1.7.0-0'
-          # - 'nightly'
+          - 'nightly'
         os:
           - ubuntu-latest
         arch: