Install manually libzstd since it was dropped from EPEL

Dockerfile_c8

@@ -3,7 +3,7 @@
 #
 # Version 0.1
 
-FROM gitlab-registry.cern.ch/linuxsupport/c8-base:latest
+FROM centos:8
 LABEL maintainer="Mihai Patrascoiu, mihai.patrascoiu@cern.ch, CERN 2020"
 
 # Add extra repositories
@@ -48,6 +48,12 @@ RUN dnf -y install epel-release dnf-plugins-core \
     xauth \
     && dnf clean all
 
+# Install manually libzstd which was dropped from EPEL
+RUN dnf install -y https://kojipkgs.fedoraproject.org//packages/zstd/1.4.4/1.el8/x86_64/libzstd-1.4.4-1.el8.x86_64.rpm \
+    https://kojipkgs.fedoraproject.org//packages/zstd/1.4.4/1.el8/x86_64/libzstd-devel-1.4.4-1.el8.x86_64.rpm \
+    https://kojipkgs.fedoraproject.org//packages/zstd/1.4.4/1.el8/x86_64/zstd-1.4.4-1.el8.x86_64.rpm \
+    https://kojipkgs.fedoraproject.org//packages/zstd/1.4.4/1.el8/x86_64/libzstd-debuginfo-1.4.4-1.el8.x86_64.rpm \
+
 # Install EOS from locally created repo
 # Note: the ADD command will reset the docker cache
 # and any commands after that point will be uncached