Update the Dockerfile from using apt-get update and yum update to meet guidelines by hub.docker.com

Author: shahmishal

5.2/amazonlinux/2/Dockerfile

@@ -2,7 +2,7 @@ FROM amazonlinux:2
 LABEL maintainer="Swift Infrastructure <[email protected]>"
 LABEL description="Docker Container for the Swift programming language"
 
-RUN yum -y update && yum -y install \
+RUN yum -y install \
   binutils \
   gcc \
   git \

5.2/centos/7/Dockerfile

@@ -2,7 +2,7 @@ FROM centos:7
 LABEL maintainer="Swift Infrastructure <[email protected]>"
 LABEL description="Docker Container for the Swift programming language"
 
-RUN yum -y update && yum install shadow-utils.x86_64 -y \
+RUN yum install shadow-utils.x86_64 -y \
   binutils \
   gcc \
   git \

5.2/centos/8/Dockerfile

@@ -4,7 +4,7 @@ LABEL description="Docker Container for the Swift programming language"
 
 RUN yum install -y https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm
 
-RUN yum -y update && yum install --enablerepo=PowerTools -y \
+RUN yum install --enablerepo=PowerTools -y \
   binutils \
   gcc \
   git \

5.2/ubuntu/16.04/Dockerfile

@@ -2,7 +2,7 @@ FROM ubuntu:16.04
 LABEL maintainer="Swift Infrastructure <[email protected]>"
 LABEL Description="Docker Container for the Swift programming language"
 
-RUN export DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true && apt-get -q update && \
+RUN export DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true && \
     apt-get -q install -y \
     libatomic1 \
     libcurl3 \

5.2/ubuntu/16.04/slim/Dockerfile

@@ -2,7 +2,7 @@ FROM ubuntu:16.04
 LABEL maintainer="Swift Infrastructure <[email protected]>"
 LABEL Description="Docker Container for the Swift programming language"
 
-RUN export DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true && apt-get -q update && \
+RUN export DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true && \
     apt-get -q install -y \
     libatomic1 \
     libcurl3 \

5.2/ubuntu/18.04/Dockerfile

@@ -2,7 +2,7 @@ FROM ubuntu:18.04
 LABEL maintainer="Swift Infrastructure <[email protected]>"
 LABEL Description="Docker Container for the Swift programming language"
 
-RUN export DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true && apt-get -q update && \
+RUN export DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true && \
     apt-get -q install -y \
     libatomic1 \
     libcurl4 \

5.2/ubuntu/18.04/slim/Dockerfile

@@ -2,7 +2,7 @@ FROM ubuntu:18.04
 LABEL maintainer="Swift Infrastructure <[email protected]>"
 LABEL Description="Docker Container for the Swift programming language"
 
-RUN export DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true && apt-get -q update && \
+RUN export DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true && \
     apt-get -q install -y \
     libatomic1 \
     libcurl4 \

5.2/ubuntu/20.04/Dockerfile

@@ -2,7 +2,7 @@ FROM ubuntu:20.04
 LABEL maintainer="Swift Infrastructure <[email protected]>"
 LABEL description="Docker Container for the Swift programming language"
 
-RUN export DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true && apt-get -q update && \
+RUN export DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true && \
     apt-get -q install -y \
     binutils \
     git \

5.2/ubuntu/20.04/slim/Dockerfile

@@ -2,7 +2,7 @@ FROM ubuntu:20.04
 LABEL maintainer="Swift Infrastructure <[email protected]>"
 LABEL description="Docker Container for the Swift programming language"
 
-RUN export DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true && apt-get -q update && \
+RUN export DEBIAN_FRONTEND=noninteractive DEBCONF_NONINTERACTIVE_SEEN=true && \
     apt-get -q install -y \
     libcurl4 \
     libxml2 \