fix(test): Update package cache before installing redis (#85)

Author: jacobo-doist

.github/workflows/tests.yml

@@ -32,6 +32,7 @@ jobs:
       - name: Install Redis
         if: matrix.backend == 'redis'
         run: |
+          sudo apt-get update
           sudo apt-get install redis -y
 
       - name: Get bitmapist-server latest version