Include index.d.ts in published package

[draperunner]

The TypeScript declaration file from v1.1.0 is not included in v1.1.0. That's because lib/main.js is the only whitelisted file.

Running npm publish --dry-run before this change:

npm notice
npm notice 📦  [email protected]
npm notice === Tarball Contents ===
npm notice 1.1kB LICENSE
npm notice 3.0kB lib/main.js
npm notice 943B  package.json
npm notice 5.1kB README.md
npm notice === Tarball Details ===
npm notice name:          promise-throttle
npm notice version:       1.1.0
npm notice package size:  3.8 kB
npm notice unpacked size: 10.1 kB
npm notice shasum:        4bc78f7b6073d03b044f84c2c49593ace277b355
npm notice integrity:     sha512-iKip8iHg5SAL3[...]Thlr4wFmTL/EA==
npm notice total files:   4
npm notice
+ [email protected]

Running npm publish --dry-run after this change:

npm notice
npm notice 📦  [email protected]
npm notice === Tarball Contents ===
npm notice 1.1kB LICENSE
npm notice 3.0kB lib/main.js
npm notice 961B  package.json
npm notice 5.1kB README.md
npm notice 406B  index.d.ts
npm notice === Tarball Details ===
npm notice name:          promise-throttle
npm notice version:       1.1.0
npm notice package size:  4.0 kB
npm notice unpacked size: 10.5 kB
npm notice shasum:        4cc4648a48ae82e09fcc167097f670c81bb2a8e0
npm notice integrity:     sha512-r7NTueAxIz4MU[...]cQB4h626wMFLA==
npm notice total files:   5
npm notice
+ [email protected]

[coveralls]

Coverage remained the same at 100.0% when pulling 6c4cfe8 on draperunner:include-typescript-declaration-in-build into ae01fcc on JMPerez:master.

[JMPerez]

Good catch, @draperunner!