Corrected yum in Dockerfile

Dockerfile

@@ -3,7 +3,7 @@ ARG BASE_IMAGE=redhat/openjdk/openjdk11
 ARG BASE_TAG=1.11
 FROM ${BASE_REGISTRY}/${BASE_IMAGE}:${BASE_TAG}
 USER root
-
+# Establish ARG and ENV variables
 ARG TARBALL=jenkinsfile-runner-dependencies-dcar-1.8
 ENV JENKINS_UC https://updates.jenkins.io
 ENV CASC_JENKINS_CONFIG /usr/share/jenkins/ref/casc
@@ -15,16 +15,15 @@ ARG user=jenkins
 ARG group=jenkins
 ARG uid=1000
 ARG gid=1000
-
 COPY LICENSE /licenses
 COPY ${TARBALL}.tar.gz /tmp/${TARBALL}.tar.gz
-
-RUN INSTALL_PKGS="git" && \
+# Install necessary packages using yum
+RUN INSTALL_PKGS="git-core" && \
     yum -y update-minimal --setopt=tsflags=nodocs \
         --security  && \
     yum -y install --setopt=tsflags=nodocs ${INSTALL_PKGS}
-
-RUN cd /tmp && tar -xzf ${TARBALL}.tar.gz \
+# Unpackage dependency tarball, create and own directories, and clean up
+RUN tar -xzf /tmp/${TARBALL}.tar.gz \
     && mkdir -p $JENKINS_HOME $TMP_DIR /usr/share/jenkins /build \
     && mv dependencies/ref /usr/share/jenkins/ref \
     && mv dependencies/app /app \
@@ -35,11 +34,10 @@ RUN cd /tmp && tar -xzf ${TARBALL}.tar.gz \
     && chown ${uid}:${gid} /usr/share/jenkins \
     && chown ${uid}:${gid} /build \
     && groupadd -g ${gid} ${group} \
-    && useradd -d "$JENKINS_HOME" -d "$TMP_DIR" -d /app -d /usr/share/jenkins -u ${uid} -g ${gid} -m -s /bin/bash ${user}
-
-RUN cd /usr/share/jenkins/ref/plugins && \
-    rm -rf github*
-
+    && useradd -d "$JENKINS_HOME" -d "$TMP_DIR" -d /app -d /usr/share/jenkins -u ${uid} -g ${gid} -m -s /bin/bash ${user} \
+    && chmod ug-s /usr/libexec/openssh/ssh-keysign \
+    && rm -rf /usr/share/jenkins/ref/plugins/github*
+# Set volumes to retain data, switch to jenkins user, and set entrypoint
 VOLUME /build
 VOLUME /usr/share/jenkins/ref/casc
 VOLUME $JENKINS_HOME