ci: add SciMLSensitivity Core6 and Core7 test groups to downstream CI

Author: AayushSabharwal

.github/workflows/Downstream.yml

@@ -49,6 +49,8 @@ jobs:
           - {user: SciML, repo: SciMLSensitivity.jl, group: Core3}
           - {user: SciML, repo: SciMLSensitivity.jl, group: Core4}
           - {user: SciML, repo: SciMLSensitivity.jl, group: Core5}
+          - {user: SciML, repo: SciMLSensitivity.jl, group: Core6}
+          - {user: SciML, repo: SciMLSensitivity.jl, group: Core7}
           - {user: SciML, repo: Catalyst.jl, group: All}
 
     steps: