fix: add forwardRef to CheckBoxGroup for v3 compatibility

[jameslahm]

[中文版模板 / Chinese template]

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• New feature
• Bug fix
• Site / documentation update
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🔗 Related issue link

Fix #30036

💡 Background and solution

add forwardRef to CheckBoxGroup

📝 Changelog

Language	Changelog
🇺🇸 English	add forwardRef to Checkbox.Group for v3 compatibility
🇨🇳 Chinese	Checkbox.Group 增加 forwardRef 以兼容v3

☑️ Self Check before Merge

⚠️ Please check all items below before review. ⚠️

• Doc is updated/provided or not needed
• Demo is updated/provided or not needed
• TypeScript definition is updated/provided or not needed
• Changelog is provided or not needed

[github-actions]

[hengkx]

Please add test.

[codecov]

Codecov Report

Merging #30039 (e488ae7) into master (aa9fac4) will not change coverage.
The diff coverage is 100.00%.

❗ Current head e488ae7 differs from pull request most recent head 96fc8f6. Consider uploading reports for the commit 96fc8f6 to get more accurate results

@@            Coverage Diff            @@
##            master    #30039   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          397       397           
  Lines         7519      7520    +1     
  Branches      2105      2105           
=========================================
+ Hits          7519      7520    +1     

Impacted Files	Coverage Δ
components/checkbox/Group.tsx	100.00% <100.00%> (ø)

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[jameslahm]

Test case is here

ant-design/components/checkbox/__tests__/group.test.js

Lines 206 to 215 in 96fc8f6

	it('should get div ref', () => {
	mount(
	<Checkbox.Group
	options={['Apple', 'Pear', 'Orange']}
	ref={node => {
	expect(node.nodeName).toBe('DIV');
	}}
	/>,
	);
	});