Update downstream action

Author: Sbozzolo

.github/workflows/downstream.yml

@@ -10,6 +10,11 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
+# Needed to allow julia-actions/cache to delete old caches that it has created
+permissions:
+  actions: write
+  contents: read
+
 jobs:
   test:
     name: downstream ${{ matrix.package }}
@@ -22,7 +27,7 @@ jobs:
           - 'ClimaLand.jl'
     steps:
       - uses: actions/checkout@v4
-      - uses: julia-actions/setup-julia@v1
+      - uses: julia-actions/setup-julia@v2
         with:
           version: '1.10'
       - uses: julia-actions/cache@v2