Make it compatible with cjs style of importing THREE

[Alchemist0823]

Because in my typescript project. three.js was included in a module. Calling THREE.BufferGeometry directly doesn't work.

What kind of change does this PR introduce? (check at least one)

• [x] Bugfix (non-breaking change which fixes an issue)
• [ ] Feature (non-breaking change which adds functionality)
• [ ] Code style update
• [ ] Refactor (refactoring or adding test which isn't a fix or add a feature)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [x] Build-related changes
• [ ] Other, please describe:

Does this PR introduce a breaking change? (check one)

• [ ] Yes
• [x] No

Did you test your solution?

• [ ] I lightly tested it in one browser
• [x] I deeply tested it in several browsers
• [ ] I wrote tests around it (unit tests, integration tests, E2E tests)

Problem Description

Solution Description

Side Effects, Risks, Impact

• [ ] N/A

Aditional comments:

[hypervillain]

What's root here?

[Alchemist0823]

HI @hypervillain, I think it's the syntax in some module system i don't know. I copied this from the most popular threejs libraries. this is the way they use to include the library to make it compatible both on nodejs module import and directly include three.js.