tools: change the order of layers in markdownlint image
Install git and golang first so that layer is not rebuilt when the
install script is changed.
FROM fedora
WORKDIR /workdir
-COPY install-markdownlint.sh /tmp
RUN dnf install -y git golang
+COPY install-markdownlint.sh /tmp
RUN /tmp/install-markdownlint.sh
ENTRYPOINT /workdir/hack/markdownlint.sh
