Another try

Author: devmotion

.github/workflows/CI.yml

@@ -29,10 +29,10 @@ jobs:
       - uses: julia-actions/cache@v1
       - uses: julia-actions/julia-buildpkg@v1
         with:
-          project: "${{ matrix.pkg == 'DiffEqProblemLibrary' && '@.' || 'lib/${{ matrix.pkg }}' }}"
+          project: "${{ matrix.pkg == 'DiffEqProblemLibrary' && '@.' || format('{{lib/{0}}}', matrix.pkg) }}"
       - uses: julia-actions/julia-runtest@v1
         with:
-          project: "${{ matrix.pkg == 'DiffEqProblemLibrary' && '@.' || 'lib/${{ matrix.pkg }}' }}"
+          project: "${{ matrix.pkg == 'DiffEqProblemLibrary' && '@.' || format('{{lib/{0}}}', matrix.pkg) }}"
       - uses: julia-actions/julia-processcoverage@v1
       - uses: codecov/codecov-action@v3
         with: