[centos] optimize gcc install

centos/Dockerfile

@@ -6,11 +6,17 @@ LABEL authors="Moritz Maxeiner <moritz.maxeiner@fu-berlin.de>"
 
 # GCC
 ENV BASH_ENV "/etc/profile"
-RUN yum install -y centos-release-scl && \
-    yum install -y epel-release && \
-    yum install -y devtoolset-9 && \
-    yum install -y rh-git218-git && \
-    yum install -y patch && \
+RUN yum install -y \
+        centos-release-scl \
+        epel-release && \
+    yum update -y && \
+    yum install -y \
+        kernel && \
+    yum install -y \
+        devtoolset-9 && \
+    yum install -y \
+        rh-git218-git \
+        patch && \
     yum clean all
 ADD bash/toolchain.sh /etc/profile.d/toolchain.sh
 ADD bash/ld-library-path.sh /etc/profile.d/ld-library-path.sh