add markdownlint-cli2 for linting markdown

Signed-off-by: Tuomo Tanskanen <tuomo.tanskanen@est.tech>

.markdownlint-cli2.yaml

@@ -0,0 +1,9 @@
+# Reference: https://github.com/DavidAnson/markdownlint-cli2#markdownlint-cli2yaml
+
+config:
+ ul-indent:
+ # Kramdown wanted us to have 3 earlier, tho this CLI recommends 2 or 4
+ indent: 3
+
+# Don't autofix anything, we're linting here
+fix: false

README.md

@@ -1,9 +1,9 @@
-Metal3 Ironic Client Container
-==============================
+# Metal3 Ironic Client Container
 
-This repo contains the files needed to build a container image with the Ironic CLI utilities, which are useful for debugging via Ironic APIs.
+This repo contains the files needed to build a container image with the Ironic
+CLI utilities, which are useful for debugging via Ironic APIs.
 
-Description
------------
+## Description
 
-When updated, builds are automatically triggered on https://quay.io/repository/metal3-io/ironic-client
+When updated, builds are automatically triggered on
+[Quay](https://quay.io/repository/metal3-io/ironic-client).

hack/markdownlint.sh

@@ -0,0 +1,20 @@
+#!/bin/sh
+# markdownlint-cli2 has config file(s) named .markdownlint-cli2.yaml in the repo
+
+set -eux
+
+IS_CONTAINER="${IS_CONTAINER:-false}"
+CONTAINER_RUNTIME="${CONTAINER_RUNTIME:-podman}"
+
+# all md files, but ignore .github
+if [ "${IS_CONTAINER}" != "false" ]; then
+ markdownlint-cli2 "**/*.md" "#.github"
+else
+ "${CONTAINER_RUNTIME}" run --rm \
+ --env IS_CONTAINER=TRUE \
+ --volume "${PWD}:/workdir:ro,z" \
+ --entrypoint sh \
+ --workdir /workdir \
+ docker.io/pipelinecomponents/markdownlint-cli2:0.9.0@sha256:71370df6c967bae548b0bfd0ae313ddf44bfad87da76f88180eff55c6264098c \
+ /workdir/hack/markdownlint.sh "$@"
+fi