chore(environment): match the tightened published-files constraint

Master narrowed `files` to the built entrypoints plus declarations; the
new environment package still carried declaration maps and `src`.

packages/util/environment/package.json

@@ -21,9 +21,7 @@
   "files": [
     "lib/index.js",
     "lib/invariant.js",
-    "lib/types/**/*.d.ts",
-    "lib/types/**/*.d.ts.map",
-    "src"
+    "lib/types/**/*.d.ts"
   ],
   "license": "BSD-3-Clause",
   "peerDependencies": {