feat: support auto check upgrade (#53)

internal/update/update.go

@@ -0,0 +1,25 @@
+package update
+
+import (
+	"strings"
+
+	"github.com/blang/semver"
+	"github.com/pkg/errors"
+	"github.com/rhysd/go-github-selfupdate/selfupdate"
+)
+
+func CheckUpgrade(currentVersion string) (bool, *selfupdate.Release, error) {
+	latest, found, err := selfupdate.DetectLatest("Li4n0/revsuit")
+	if err != nil {
+		return false, nil, errors.Wrap(err, "error when detecting version")
+	}
+
+	v, err := semver.Parse(strings.TrimPrefix(currentVersion, "v"))
+	if err != nil {
+		return false, nil, errors.Wrap(err, "error when parse version")
+	}
+	if !found || latest.Version.LTE(v) {
+		return false, nil, nil
+	}
+	return true, latest, nil
+}