CI: fix RAR backend installation (#1697)

.github/workflows/tests.yaml

@@ -68,7 +68,7 @@ jobs:
       run: brew install rar
       if: ${{ runner.os == 'macOS' }}
     - name: Install choco dependencies (Windows)
-      run: choco install unrar
+      run: choco install 7zip
       if: ${{ runner.os == 'Windows' }}
     - name: Install pip dependencies
       if: steps.cache.outputs.cache-hit != 'true'