docker: Update alpine packages with security fixes on build
Created by: kevinwojo
In response to: https://github.com/sourcegraph/sourcegraph/issues/32679
We need an updated version of the OpenSSL packages. apk update
only refreshes the repository information. It does not enforce the latest package installed. Adding apk upgrade
ensures that we are receiving the most critical security fixes.
Test plan
Running through CI smoke tests. Verified the build locally on my workstation and kicking off a dry-run.