Fix git 2.x download URL for the maven scm plugin (#947)

Motivation:

The git 2.x download URL for the maven scm plugin are no longer
accessible.

Modification:

Switch to URL used by the opensource.blueoptima.com website.

Result:

Builds should no longer fail to download git 2.x for the maven scm
plugin.

Author: normanmaurer

docker/Dockerfile.cross_compile_aarch64

@@ -18,7 +18,7 @@ WORKDIR $SOURCE_DIR
 RUN sed -i -e 's/^mirrorlist/#mirrorlist/g' -e 's/^#baseurl=http:\/\/mirror.centos.org\/centos\/$releasever\//baseurl=https:\/\/linuxsoft.cern.ch\/centos-vault\/\/7.6.1810\//g' /etc/yum.repos.d/CentOS-Base.repo
 
 # We want to have git 2.x for the maven scm plugin and also for boringssl
-RUN yum install -y http://opensource.wandisco.com/centos/6/git/x86_64/wandisco-git-release-6-1.noarch.rpm
+RUN yum install -y https://opensource.blueoptima.com/centos/6/git/x86_64/wandisco-git-release-6-1.noarch.rpm
 
 # Install requirements
 RUN  set -x && \