chore(deps): bump actions/cache from 3 to 4 (#20)

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Author: dependabot[bot]

.github/workflows/ci.yml

@@ -27,7 +27,7 @@ jobs:
           elixir-version: ${{ env.ELIXIR_VERSION }}
 
       - name: Set up cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         id: mix-cache
         with:
           path: |