Cache linting deps

Author: AstroPatty

.github/workflows/build.yaml

@@ -1,4 +1,4 @@
-name: opencosmo CI
+nme: opencosmo CI
 
 on:
   pull_request:
@@ -27,6 +27,7 @@ jobs:
         uses: actions/setup-python@v4
         with:
           python-version: '3.13'
+          cache: poetry
       - name: setup mpi
         uses: mpi4py/setup-mpi@v1
       - name: Install Poetry