Fix module resolution in typescript

[jannikac]

Hi, I've found another small issue when using typescript with this package. When using the tsconfig options module: "NodeNext" and moduleResolution: "NodeNext", tsc showed the following error:

test.ts:1:18 - error TS7016: Could not find a declaration file for module 'ical'. '/icalpath/node_modules/ical/dist/ical.js' implicitly has an 'any' type.
  There are types at '/icalpath/node_modules/ical/dist/types/module.d.ts', but this result could not be resolved when respecting package.json "exports". The 'ical.js' library may need to update its package.json or typings.

1 import ICAL from "ical";
                   ~~~~~~~
Found 1 error in test.ts:1

This was fixed by b3821e0.

Also I noticed that when using typescript and go to definition VSCode would go to the .d.ts files instead of the js sources. This was fixed by adding the declarationmaps to the package which allow VSCode or another language server to connect the declarations and the source js files. 9401238.

[coveralls]

Pull Request Test Coverage Report for Build 10113229055

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 98.16%

---

Totals
Change from base Build 10031055480:	0.0%
Covered Lines:	9454
Relevant Lines:	9616

---

💛 - Coveralls

[kewisch]

Sorry for the delay on your reviews @jannikac. My attention usually comes in bursts, feel free to ping me if you need anything!