In commit 2a6f7eac80, the Dockerfile under the section "Name your build
stages" was updated, the build stage was renamed from "builder" to
"build". However, the next section was still using the old build stage
name.
Fixes: 2a6f7eac80 ("freshness: update top pages in the build section")
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>