Keep Pyomo 6.4.2

Author: bknueven

Diff for: .github/workflows/pyotracker.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        pyomo-version: [6.5.0, main]
+        pyomo-version: [6.4.2, main]
     steps:
       - uses: actions/checkout@v3
       - uses: conda-incubator/setup-miniconda@v2