Generate release notes (#1774)

* ci: generate better release notes

* scripts: rename generate-release-note.sh

* ci/release: check out all the history

* ci/release: accept version from input

scripts/generate-release-notes.sh

@@ -0,0 +1,69 @@
+#!/usr/bin/env bash
+
+if [ ! -e "src/api/api.h" ]; then
+  echo "Please run this script from the root directory of Lite XL."; exit 1
+fi
+
+show_help() {
+  echo
+  echo "Release notes generator for lite-xl releases."
+  echo "USE IT AT YOUR OWN RISK!"
+  echo
+  echo "Usage: $0 <OPTIONS>"
+  echo
+  echo "Available options:"
+  echo
+  echo "--version    Use this version instead of git tags or GitHub outputs."
+  echo "--debug      Debug this script."
+  echo "--help       Show this message."
+  echo
+}
+
+main() {
+  local version
+
+  for i in "$@"; do
+    case $i in
+      --debug)
+        set -x
+        shift
+        ;;
+      --help)
+        show_help
+        exit 0
+        ;;
+      --version)
+        version="$2"
+        shift
+        shift
+        ;;
+      *)
+        # unknown option
+        ;;
+    esac
+  done
+
+  if [[ -n $1 ]]; then
+    show_help
+    exit 0
+  fi
+
+  if [[ -z "$version" ]]; then
+    if [[ "$GITHUB_REF" == "refs/tags/"* ]]; then
+      version="${GITHUB_REF##*/}"
+    else
+      version="$(git describe --tags $(git rev-list --tags --max-count=1))"
+      if [[ $? -ne 0 ]]; then version=""; fi
+    fi
+  fi
+
+  if [[ -z "$version" ]]; then
+    echo "error: cannot get latest git tag"
+    exit 1
+  fi
+
+  export RELEASE_TAG="$version"
+  envsubst '$RELEASE_TAG' > release-notes.md < resources/release-notes.md
+}
+
+main "$@"