(fix/deps): use rootDir: './src' instead of './'

- because './src' is actually being used as the rootDir

(deps): I deprecated this buggy option in TSDX but my PR has yet to be
released
- it outputs a warning in newer versions but no harm and only benefit
  in upgrading earlier

tsconfig.json

@@ -6,7 +6,7 @@
  "importHelpers": true,
  "declaration": true,
  "sourceMap": true,
- "rootDir": "./",
+ "rootDir": "./src",
  "strict": true,
  "noUnusedLocals": true,
  "noUnusedParameters": true,