Test on min, lts, and pre instead of 1.6 and nightly

Author: andreasnoack

.github/workflows/ci.yml

@@ -12,9 +12,10 @@ jobs:
       fail-fast: false
       matrix:
         version:
-          - '1.6'
+          - 'min'
+          - 'lts'
           - '1' # automatically expands to the latest stable 1.x release of Julia
-          - 'nightly'
+          - 'pre'
         os:
           - ubuntu-latest
           - macOS-latest