feat: add UpgradeType function which simplifies what difference is there between two tags

tagcmp.go

@@ -184,6 +184,42 @@ func (curTag Tag) UpgradeElement(newTag Tag) (Tag, error) {
 	return diff, nil
 }
 
+// UpgradeType takes exit from UpgradeElemene and returns a numeric representation of upgrade or downgrade
+// 1/-1: patch 2/-2: minor 4/-4: major 0: no change
+func UpgradeType(t Tag) int {
+	var major, minor, patch int
+	major = strconv.Atoi(t.Major)
+	if t.MissingMinor {
+		minor = 0
+	} else {
+		minor = strconv.Atoi(t.Minor)
+	}
+	if t.MissingPatch {
+		patch = 0
+	} else {
+		patch := strconv.Atoi(t.Patch)
+	}
+	if major > 0 {
+		return 4
+	}
+	if major < 0 {
+		return -4
+	}
+	if minor > 0 {
+		return 2
+	}
+	if minor < 0 {
+		return -2
+	}
+	if patch > 0 {
+		return 1
+	}
+	if patch < 0 {
+		return -1
+	}
+	return 0
+}
+
 // CommitHashPattern matches commit-like hash tags
 var CommitHashPattern = "^[a-f0-9]{7,40}$"