Add bumpVersion function

vars/bumpVersion.groovy

@@ -0,0 +1,26 @@
+String call(String version, String flag = 'patch') {
+    List<String> versionArray = version.tokenize('.')
+    int major = versionArray[0] as int
+    int minor = versionArray[1] as int
+    int patch = versionArray[2] as int
+
+    switch (flag) {
+        case 'major':
+            major++
+            minor = 0
+            patch = 0
+            break
+        case 'minor':
+            minor++
+            patch = 0
+            break
+        case 'patch':
+            patch++
+            break
+        default:
+            echo "Invalid flag: $flag"
+            return version
+    }
+
+    return "${major}.${minor}.${patch}"
+}