Vulnerabilities fixes & Upgrade to Ubuntu 22.04 (#190)

Author: VeronikaSolovei9

Dockerfile

@@ -1,7 +1,7 @@
-FROM ubuntu:20.04 AS build
+FROM ubuntu:22.04 AS build
 RUN apt-get update && \
     apt-get -y upgrade && \
-    apt-get install -y wget
+    apt-get install -y --no-install-recommends wget ca-certificates
 ENV GO_INSTALLER=go1.19.5.linux-amd64.tar.gz
 WORKDIR /tmp
 RUN wget https://dl.google.com/go/$GO_INSTALLER && \
@@ -12,7 +12,7 @@ ENV GOROOT=/usr/local/go
 ENV PATH=$GOROOT/bin:$PATH
 ENV GOPROXY="https://proxy.golang.org"
 RUN apt-get update && \
-    apt-get install -y git && \
+    apt-get install -y --no-install-recommends git && \
     apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
 ENV CGO_ENABLED 0
 COPY ./ ./
@@ -22,19 +22,18 @@ ARG TEST="true"
 RUN if [ "$TEST" != "false" ]; then ./validate.sh ; fi
 RUN go build -mod=vendor -ldflags "-X github.com/prebid/prebid-cache/version.Ver=`git describe --tags` -X github.com/prebid/prebid-cache/version.Rev=`git rev-parse HEAD`" .
 
-FROM ubuntu:20.04 AS release
+FROM ubuntu:22.04 AS release
 LABEL maintainer="hans.hjort@xandr.com" 
 RUN apt-get update && \
-    apt-get install --assume-yes apt-utils && \
-    apt-get install -y ca-certificates && \
+    apt-get install -y --no-install-recommends ca-certificates && \
     apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
 WORKDIR /usr/local/bin/
 COPY --from=build /app/prebid-cache/prebid-cache .
 RUN chmod a+xr prebid-cache
 COPY --from=build /app/prebid-cache/config.yaml .
 RUN chmod a+r config.yaml
-RUN adduser prebid_user
-USER prebid_user
+RUN addgroup --system --gid 2001 prebidgroup && adduser --system --uid 1001 --ingroup prebidgroup prebid
+USER prebid
 EXPOSE 2424
 EXPOSE 2525
 ENTRYPOINT ["/usr/local/bin/prebid-cache"]