docs(swc): add @swc/core to install step

[mayvagio2016]

Rollup Plugin Name: swc

This PR contains:

• [ ] bugfix
• [ ] feature
• [ ] refactor
• [x] documentation
• [ ] other

Are tests included?

• [ ] yes (bugfixes and features will not be merged without tests)
• [x] no

Breaking Changes?

• [ ] yes (breaking changes will not be merged unless absolutely necessary)
• [x] no

If yes, then include "BREAKING CHANGES:" in the first commit message body, followed by a description of what is breaking.

List any relevant issue numbers:

Description