add MathOptInterface and PowerModels to downstream tests

Author: oameye

.github/workflows/downstream.yml

@@ -14,6 +14,8 @@ jobs:
         os: ['ubuntu-latest']
         package:
           - {user: jump-dev, repo: JuMP.jl}
+          - {user: jump-dev, repo: MathOptInterface.jl}
+          - {user: lanl-ansi, repo: PowerModels.jl}
     steps:
       - uses: actions/checkout@v6
       - uses: julia-actions/setup-julia@v2