Upgrade alpine to 3.13.5 (#53)

Bjørn · web-flow · commit fe153382904e · 2021-05-28T13:22:48.000+02:00
diff --git a/Dockerfile-goreleaser b/Dockerfile-goreleaser
@@ -1,4 +1,4 @@
-FROM alpine:3.12.1 as builder
+FROM alpine:3.13.5 as builder
 
 RUN apk update
 RUN apk add ca-certificates
