use wkhtmltox 0.12.4 to support TOC

Author: PhilippSalvisberg

docker/Dockerfile

@@ -8,7 +8,16 @@ RUN yum install -y https://centos7.iuscommunity.org/ius-release.rpm
 RUN yum update -y
 RUN yum install -y python36u python36u-libs python36u-devel python36u-pip
 RUN yum install -y git
-RUN yum install -y https://github.com/wkhtmltopdf/wkhtmltopdf/releases/download/0.12.5/wkhtmltox-0.12.5-1.centos7.x86_64.rpm
+RUN yum install -y wget
+
+# Install wkhtmltox 0.12.4 since 0.12.5 cannot create TOCs, see https://github.com/wkhtmltopdf/wkhtmltopdf/issues/3995
+# RUN yum install -y https://github.com/wkhtmltopdf/wkhtmltopdf/releases/download/0.12.5/wkhtmltox-0.12.5-1.centos7.x86_64.rpm
+RUN yum install -y yum install -y wkhtmltopdf
+RUN wget -q https://github.com/wkhtmltopdf/wkhtmltopdf/releases/download/0.12.4/wkhtmltox-0.12.4_linux-generic-amd64.tar.xz -O /tmp/wkhtmltox.tar.xz && \
+    tar xvf /tmp/wkhtmltox.tar.xz -C /tmp && \
+    cp -rp /tmp/wkhtmltox/* /usr/local && \
+    rm -rf /tmp/wkhtmltox*
+
 RUN pip3.6 install --upgrade pip
 RUN pip3.6 install mkdocs \
                    mkdocs-material \