try to install redis

Author: ktoso

.github/workflows/pull_request.yml

@@ -15,7 +15,8 @@ jobs:
     name: Unit tests
     uses: swiftlang/github-workflows/.github/workflows/swift_package_test.yml@main
     with:
-      linux_pre_build_command: apt-get update -y && apt-get install redis -y && systemctl start redis-stack-server
+      # since we don't have systemctl, we run the redis server manually in the background
+      linux_pre_build_command: apt-get update -y && apt-get install redis -y && redis-server &
       linux_exclude_swift_versions: "[{\"swift_version\": \"5.8\"}]"
       linux_env_vars: REDIS_URL=redis
       enable_windows_checks: false