workflows: centos-7: Use Extra repo's epel-release

Signed-off-by: Hiroshi Hatake <[email protected]>

.github/workflows/build.yaml

@@ -48,8 +48,7 @@ jobs:
           sed -i -e "s/^#baseurl=http:\/\/mirror.centos.org/baseurl=http:\/\/vault.centos.org/g" /etc/yum.repos.d/CentOS-Base.repo && \
           yum -y update && \
           yum install -y ca-certificates cmake gcc gcc-c++ git make wget && \
-          wget http://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm && \
-          rpm -ivh epel-release-latest-7.noarch.rpm && \
+          yum install -y epel-release && \
           yum install -y cmake3
         shell: bash