fix: Change tsconfig target to prevent transpile ES5 error

Author: cerpinn

tsconfig.json

@@ -2,6 +2,7 @@
   // see https://www.typescriptlang.org/tsconfig to better understand tsconfigs
   "include": ["src", "types"],
   "compilerOptions": {
+    "target": "ES6",
     "module": "esnext",
     "lib": ["dom", "esnext"],
     "importHelpers": true,
@@ -30,6 +31,6 @@
     // error out if import and file system have a casing mismatch. Recommended by TS
     "forceConsistentCasingInFileNames": true,
     // `tsdx build` ignores this option, but it is commonly used when type-checking separately with `tsc`
-    "noEmit": true,
+    "noEmit": true
   }
 }