Apply suggestions from code review

Author: JoshuaLampert

.github/workflows/Downgrade.yml

@@ -53,6 +53,7 @@ jobs:
           skip: LinearAlgebra,Printf,SparseArrays,DelimitedFiles,Test
           projects: ., test
           mode: forcedeps
+          julia_version: ${{ matrix.version }}
       - uses: julia-actions/julia-buildpkg@v1
         env:
           PYTHON: ""