Update actions/cache@v2 -> v4 in ci.yml ref: https://github.com/dwyl/elixir-auth-google/actions/runs/13636781529/job/38117411175#step:1:36

Author: nelsonic

.github/workflows/ci.yml

@@ -18,7 +18,7 @@ jobs:
         elixir-version: '1.14.2' # Define the elixir version [required]
         otp-version: '25.1.2' # Define the OTP version [required]
     - name: Restore dependencies cache
-      uses: actions/cache@v2
+      uses: actions/cache@v4
       with:
         path: deps
         key: ${{ runner.os }}-mix-${{ hashFiles('**/mix.lock') }}