Only test 1.6, 1.9, 1

Author: MilesCranmer

.github/workflows/main.yml

@@ -22,10 +22,9 @@ jobs:
           - '3.9'
           - '3.12'
         julia-version:
-          - '1.4'
-          - '1.7'
-          - '1.8'
+          - '1.6'
           - '1.9'
+          - '1'
         exclude:
           - os: ubuntu-latest
             architecture: x86