update dockerfiles

ci/image/Dockerfile.dotnet-centos7-net6-build

@@ -1,5 +1,4 @@
 FROM centos:7
-# Dockerfile.dotnet-centos7-net6-test is equal to Dockerfile.dotnet-centos7-net6-build
 
 USER root
 WORKDIR /

ci/image/Dockerfile.dotnet-centos7-net6-test

@@ -1,48 +1 @@
-FROM centos:7
-# Dockerfile.dotnet-centos7-net6-test is equal to Dockerfile.dotnet-centos7-net6-build
-
-USER root
-WORKDIR /
-
-# update OS and install basic tools
-RUN yum -y update && \
-    yum -y install epel-release && \
-    yum -y install centos-release-scl && \
-    yum -y install git && \
-    yum -y install which && \
-    yum -y install zstd && \
-    yum -y install jq \
-
-# python
-RUN yum -y install python36
-RUN python3 -V
-RUN pip3 install -U pip
-RUN pip3 install -U snowflake-connector-python
-
-# aws
-RUN pip3 install -U awscli
-RUN aws --version
-
-# gosu
-RUN curl -o /usr/local/bin/gosu -SL "https://github.com/tianon/gosu/releases/download/1.11/gosu-amd64"
-RUN chmod +x /usr/local/bin/gosu
-
-# Install build tools
-RUN yum -y groupinstall 'Development Tools'
-RUN yum -y install centos-release-scl
-RUN yum -y install devtoolset-8-gcc*
-SHELL [ "/usr/bin/scl", "enable", "devtoolset-8"]
-
-# dotnet-sdk-6.0
-RUN rpm -Uvh https://packages.microsoft.com/config/centos/7/packages-microsoft-prod.rpm
-RUN yum -y install --exclude 1:openssl-libs-1.0.2k-26.el7_9.x86_64 dotnet-sdk-6.0
-
-# workspace
-RUN mkdir -p /home/user && \
-    chmod 777 /home/user
-WORKDIR /home/user
-
-# entry point
-COPY scripts/entrypoint.sh /usr/local/bin/entrypoint.sh
-RUN chmod +x /usr/local/bin/entrypoint.sh
-ENTRYPOINT ["/usr/local/bin/entrypoint.sh"]
+FROM nexus.int.snowflakecomputing.com:8086/docker/client-dotnet-centos7-net6-build:1