Add declaration maps

Author: wooorm

Diff for: .gitignore

@@ -1,5 +1,6 @@
 *.d.ts
 *.log
+*.map
 *.tsbuildinfo
 .DS_Store
 coverage/

Diff for: package.json

@@ -25,6 +25,7 @@
   },
   "exports": "./index.js",
   "files": [
+    "index.d.ts.map",
     "index.d.ts",
     "index.js",
     "lib/"

Diff for: tsconfig.json

@@ -2,6 +2,7 @@
   "compilerOptions": {
     "checkJs": true,
     "customConditions": ["development"],
+    "declarationMap": true,
     "declaration": true,
     "emitDeclarationOnly": true,
     "exactOptionalPropertyTypes": true,