feat: add updater package for in-place self-update

internal/updater/version.go

@@ -0,0 +1,35 @@
+package updater
+
+import (
+	"strings"
+
+	"golang.org/x/mod/semver"
+)
+
+func trimV(v string) string {
+	return strings.TrimPrefix(strings.TrimSpace(v), "v")
+}
+
+func canonical(v string) string {
+	v = strings.TrimSpace(v)
+	if v == "" {
+		return ""
+	}
+	if !strings.HasPrefix(v, "v") {
+		v = "v" + v
+	}
+	if !semver.IsValid(v) {
+		return ""
+	}
+
+	return v
+}
+
+func IsNewer(current, latest string) bool {
+	c, l := canonical(current), canonical(latest)
+	if c == "" || l == "" {
+		return false
+	}
+
+	return semver.Compare(l, c) > 0
+}