Revert back to tsconfig.json

`awesome-typescript-loader` ignores the config if it doesn't end with `.json`.

Author: marvinhagemeister

src/lib/ts-config.js

@@ -0,0 +1,11 @@
+{
+  "compilerOptions": {
+		"noEmitHelpers": true,
+    "module": "es2015",
+		"moduleResolution": "node",
+    "target": "es2017",
+    "noImplicitAny": false,
+    "sourceMap": true,
+    "jsx": "preserve"
+  }
+}

src/lib/tsconfig.json

@@ -58,7 +58,7 @@ export default env => {
 	env.manifest = readJson(src('manifest.json')) || {};
 
 	// use user specified tsconfig.json if present
-	let tsconfig = resolve(__dirname, 'ts-config.js');
+	let tsconfig = resolve(__dirname, 'tsconfig.json');
 	try {
 		statSync(src('tsconfig.json'));
 		tsconfig = src('tsconfig.json');