Upgrade dependent packages to the latest version

[yhatt]

This PR will upgrade dependent packages to the latest version via yarn upgrade --latest.

Notable changes

• Upgrade Marp Core to v1.1.0 and Marp CLI to v0.17.3
  • [Marp Core] default theme CSS has a minor fix because of bumped github-markdown-css v4
  • [Marp CLI] PPTX export does no longer make multiple master slides (from v0.17.2)
  • [Marp CLI] Exported HTML is getting more robust against the exception in an edge case (from v0.17.2)

• Bumped to Prettier v2! ✨
  • Now trailingComma has a default value es5 so removed a specific option from our project.
  • Run yarn format --write to follow new default formatting (arrowParens: always).

• Bumped Rollup to v2 and its TS plugin to v4.
  • Fixed tsconfig.json to make compatible with rollup plugin.

• Fix CVE-2020-7598 in deep dependencies tentatively.
  • The same resolutions as Marp CLI have been applied. I suppose fix on these would take a long time to resolve due to including inactive packages.

[yhatt]

Due to resolutions for dependent packages, vsce cannot package into VSIX currently. npm does not recognize resolutions field.

Adding --yarn option will success to create VSIX but installed package won't work.