Fix Godot version regex parsing

Author: Bromeon

godot-codegen/src/godot_version.rs

@@ -28,17 +28,11 @@ pub struct GodotVersion {
 
 pub fn parse_godot_version(version_str: &str) -> Result<GodotVersion, Box<dyn Error>> {
     let regex = Regex::new(
-        r#"(\d+)\.(\d+)(?:\.(\d+))?\.(alpha|beta|dev|stable)[0-9]*\.(?:mono)\.(?:(?:official|custom_build)\.([a-f0-9]+)|official)"#,
+        r#"(\d+)\.(\d+)(?:\.(\d+))?\.(alpha|beta|dev|stable)[0-9]*\.(?:mono\.)?(?:(?:official|custom_build)\.([a-f0-9]+)|official)"#,
     )?;
 
-    let caps = regex.captures(version_str).ok_or("Regex capture failed")?;
-
-    let fail = || {
-        format!(
-            "Version substring could not be matched in '{}'",
-            version_str
-        )
-    };
+    let fail = || format!("Version substring cannot be parsed: `{}`", version_str);
+    let caps = regex.captures(version_str).ok_or_else(fail)?;
 
     Ok(GodotVersion {
         full_string: caps.get(0).unwrap().as_str().to_string(),