feat: adds a hook before MSICreator.create() is called

[mako-taco]

This allows users to take advantage of the template configuration that electron-wix-msi provdes (see https://github.com/felixrieseberg/electron-wix-msi#template-configuration-optional for details)

• I have read the contribution documentation for this project.
• I agree to follow the code of conduct that this project follows, as appropriate.
• The changes are appropriately documented (if applicable).
• The changes have sufficient test coverage (if applicable).
• The testsuite passes successfully on my local machine (if applicable).

Summarize your changes:

[mako-taco]

It doesn't appear like there are any tests for MakerWix.ts right now, unless I'm missing something?

[malept]

It doesn't appear like there are any tests for MakerWix.ts right now, unless I'm missing something?

There aren't, but that doesn't mean you can't add them. What would tests look like without running the WiX maker? (Because that already takes a really long time, and the testsuite takes a while to run as it is.)

[mako-taco]

It doesn't appear like there are any tests for MakerWix.ts right now, unless I'm missing something?

There aren't, but that doesn't mean you can't add them. What would tests look like without running the WiX maker? (Because that already takes a really long time, and the testsuite takes a while to run as it is.)

We can optionally pass a function which returns an MSICreator to make (defaulting to (config) => new MSICreator(config)), then mock that in tests, and assert that beforeCreate is called. sound good?

[whysofunky]

Do you have an estimate of when this change will be published?

[MarshallOfSound]

@whysofunky v6.0.0-beta.30 went out today 👍