chore(create-app): add type="button" to satisfy eslint rule

[TeXmeijin]

@see https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/button-has-type.md

Description

Some of create-app template has <button> element that has not 'type' attribute.

So, following eslint rules will show errors.

• https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/button-has-type.md
• https://eslint.vuejs.org/rules/html-button-has-type.html

So I added type="button" to <button> element.

Additional context

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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