feat!: introduce ChronoTomatoVersion

- set version from `runtime/debug.Main.Version`
- use latest git tag as fallback
- allow version to be overwritten via ldflags
- this will break `go build .` and `go install .`

internal/metadata/version.go

@@ -0,0 +1,33 @@
+package metadata
+
+import (
+	"os/exec"
+	"runtime/debug"
+	"strings"
+)
+
+var ChronoTomatoVersion = "" // The GoTomato version
+
+func stripVersionPrefix(version string) string {
+	return strings.TrimLeft(version, "v")
+}
+
+func getLatestTag() string {
+	bytes, _ := exec.Command("git", "describe", "--tags").Output()
+	output := strings.TrimSpace(string(bytes))
+	return stripVersionPrefix(output)
+}
+
+// set GoTomatoVersion from runtime/debug.Main.Version
+// use latest git tag as fallback
+// can be overwritten via ldflags (e,g. by goreleaser)
+func init() {
+	if ChronoTomatoVersion == "" {
+		info, _ := debug.ReadBuildInfo()
+		if info.Main.Version != "(devel)" {
+			ChronoTomatoVersion = stripVersionPrefix(info.Main.Version)
+		} else {
+			ChronoTomatoVersion = getLatestTag()
+		}
+	}
+}