Update tsconfig.json (#100)

Add incremental item into default tsconfig.json, more references: https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-5.html#--incremental-improvements

Author: Kennytian

template/tsconfig.json

@@ -15,6 +15,7 @@
     // "rootDir": "./",                       /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
     // "removeComments": true,                /* Do not emit comments to output. */
     "noEmit": true,                           /* Do not emit outputs. */
+    "incremental": true,                      /* Enable incremental compilation */
     // "importHelpers": true,                 /* Import emit helpers from 'tslib'. */
     // "downlevelIteration": true,            /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */
     "isolatedModules": true,                  /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */
@@ -58,4 +59,4 @@
   "exclude": [
     "node_modules", "babel.config.js", "metro.config.js", "jest.config.js"
   ]
-}
+}