Fix: Use openvas-scanner:edge as default base image

bjoernricks · nichtsfrei · commit 3a700b70857e · 2023-07-10T12:50:52.000+02:00
openvas-scanner:unstable doesn't exist or is outdated. Edge contains the
lastest openvas-scanner image built from the main branch.
diff --git a/.docker/prod.Dockerfile b/.docker/prod.Dockerfile
@@ -1,4 +1,4 @@
-ARG VERSION=unstable
+ARG VERSION=edge
 
 FROM golang AS tools
 COPY smoketest /usr/local/src
