Upgrade Node.js and dependent packages

[yhatt]

Notable changes

• Upgrade Marp Core to v3.5.0.
• Upgrade Node.js to 18.14.1.
  • https://nodejs.org/en/blog/vulnerability/february-2023-security-releases/
• Removed stylelint-config-prettier from dependency.
  • Some style rules were deprecated and no longer required to disable duplicated rules with Prettier by stylelint-config-prettier.
  • https://stylelint.io/migration-guide/to-15#deprecated-stylistic-rules
• In the latest Jest, jest.restoreAllMocks() seems to restore also other kind of mocks than jest.spyOn().
  • Updated tests to ensure restoring every mocked spies by try-finally and afterEach().