Test on current stable release instead of nightly

Nightly is not generally going to work with autodiff, while this was not testing on current stable release (v1.7) which is what most users are likely on. We usually prefer to test on stable + LTS.

Author: ChrisRackauckas

.github/workflows/CI.yml

@@ -11,7 +11,7 @@ jobs:
       matrix:
         version:
           - '1.6'
-          - 'nightly'
+          - '1'
         os:
           - ubuntu-latest
         arch:
@@ -56,4 +56,4 @@ jobs:
               using Documenter: DocMeta, doctest
               using OperatorLearning
               DocMeta.setdocmeta!(OperatorLearning, :DocTestSetup, :(using OperatorLearning); recursive=true)
-              doctest(OperatorLearning)'
+              doctest(OperatorLearning)'