fix: add missing packages on final layer

Closes coop-cloud/organising#598

Dockerfile

@@ -1,23 +1,29 @@
+# Build image
 FROM golang:1.21-alpine AS build
 
 ENV GOPRIVATE coopcloud.tech
 
 RUN apk add --no-cache \
-  ca-certificates \
   gcc \
   git \
   make \
   musl-dev
 
-RUN update-ca-certificates
-
 COPY . /app
 
 WORKDIR /app
 
 RUN CGO_ENABLED=0 make build
 
-FROM scratch
+# Release image ("slim")
+FROM alpine:3.19.1
+
+RUN apk add --no-cache \
+  ca-certificates \
+  git \
+  openssh
+
+RUN update-ca-certificates
 
 COPY --from=build /app/abra /abra