Update dockerfile to install security updates

Plus hacks to build the binary in the dockerfile as it is a
bit of a pain to build the older style project with newer
go tooling.

Author: kppullin-nt

.dockerignore

@@ -1,17 +1,24 @@
-FROM debian:10-slim
+FROM golang:1.20.4 AS builder
+
+COPY . ./src/github.com/NextDeveloperTeam/postgres_exporter
+
+WORKDIR /go/src/github.com/NextDeveloperTeam/postgres_exporter
+
+RUN GO111MODULE=off go run mage.go binary \
+  && cp ./bin/postgres_exporter_v0.8.0_linux-amd64/postgres_exporter /postgres_exporter
+
+FROM debian:11-slim
 RUN useradd -u 20001 postgres_exporter
 
 # Install certs and create home directory needed by the AWS SDK
-RUN apt update && apt install ca-certificates -y \
+RUN apt-get update && apt-get upgrade -y && apt install ca-certificates -y \
   && mkdir /home/postgres_exporter \
   && chown postgres_exporter:postgres_exporter /home/postgres_exporter \
   && rm -rf /var/lib/{apt,dpkg,cache,log}/
 
 USER postgres_exporter
 
-ARG binary
-
-COPY $binary /postgres_exporter
+COPY --chown=postgres_exporter:postgres_exporter --from=builder /postgres_exporter /postgres_exporter
 
 EXPOSE 9187