Simplify TypeScript configuration (firebase#504)

Author: merlinnot

tsconfig.json

@@ -1,12 +1,8 @@
 {
   "compilerOptions": {
-    "lib": ["es2017"],
-    "module": "commonjs",
-    "noImplicitAny": false,
-    "outDir": ".tmp",
     "resolveJsonModule": true,
     "sourceMap": true,
-    "target": "es2017"
   },
-  "include": ["src/**/*.ts", "spec/**/*.ts"]
+  "extends": "./tsconfig.release.json",
+  "include": ["./src/**/*.ts", "./spec/**/*.ts"]
 }

tsconfig.release.json

@@ -7,7 +7,7 @@
     "outDir": "lib",
     "stripInternal": true,
     "target": "es2017",
-    "typeRoots": ["node_modules/@types"]
+    "typeRoots": ["./node_modules/@types"]
   },
-  "files": ["src/index.ts"]
+  "files": ["./src/index.ts"]
 }