Test GEM

Author: pbrubeck

.github/workflows/core.yml

@@ -212,6 +212,7 @@ jobs:
           pip install -U pip
           pip install --group ./firedrake-repo/pyproject.toml:ci
 
+          pip install -I "firedrake-fiat @ git+https://github.com/firedrakeproject/fiat.git@pbrubeck/test/gem"
           firedrake-clean
           pip list