Add quotes to spec to test build.

Author: nkoukpaizan

.github/workflows/spack_cpu_build.yaml

@@ -174,7 +174,7 @@ jobs:
 
       - name: Test Build
         run: cd $(spack -e . location --build-dir exago@develop) && ctest -VV
-        if: ${{ matrix.spack_spec == exago@develop+mpi+ipopt+hiop~python~raja ^hiop~raja~sparse}}
+        if: ${{ matrix.spack_spec == 'exago@develop+mpi+ipopt+hiop~python~raja ^hiop~raja~sparse'}}
 
       # Push with force to override existing binaries...
       - name: Push binaries to buildcache