Added Makefile and release script

Makefile

@@ -0,0 +1,12 @@
+.PHONY: image release clean
+
+all: image
+
+image:
+	@docker build -t prologic/action-remark-lint .
+
+release:
+	@./tools/release.sh
+
+clean:
+	@git clean -f -d -X

tools/release.sh

@@ -0,0 +1,30 @@
+#!/bin/sh
+
+# Get the highest tag number
+VERSION="$(git describe --abbrev=0 --tags)"
+VERSION=${VERSION:-'v0.0.0'}
+
+# Strip the v prefix
+VERSION="$(echo "$VERSION" | sed -e 's/^v\(.*\)/\1/')"
+
+# Get number parts
+MAJOR="${VERSION%%.*}"
+VERSION="${VERSION#*.}"
+MINOR="${VERSION%%.*}"
+VERSION="${VERSION#*.}"
+PATCH="${VERSION%%.*}"
+VERSION="${VERSION#*.}"
+
+# Increase version
+PATCH=$((PATCH + 1))
+
+TAG="${1}"
+
+if [ x"${TAG}" = x"" ]; then
+  TAG="v${MAJOR}.${MINOR}.${PATCH}"
+fi
+
+echo "Releasing ${TAG} ..."
+
+git tag -a -s -m "Release ${TAG}" "${TAG}"
+git push --tags