feat: make data property protected to enable inheritance

BREAKING CHANGE: Changed `data` property from private to protected to allow
subclasses to access internal state. This enables better extensibility but
may affect consumers who subclass DrupalJsonApiParams.

- Changed `private data` to `protected data` in DrupalJsonApiParams class
- Allows subclasses to access and modify internal query state
- Improves library extensibility for advanced use cases

Author: d34dman

src/index.ts

@@ -60,7 +60,8 @@ export interface DrupalJsonApiParamsInterface {
   getQueryObject(): object;
 }
 export class DrupalJsonApiParams implements DrupalJsonApiParamsInterface {
-  private data: DrupalJsonApiParamsStore = {
+
+  protected data: DrupalJsonApiParamsStore = {
     filter: {},
     include: [],
     page: undefined,