fix: spec compatible "browser" mapping (#1018)

per unofficial "spec" https://github.com/defunctzombie/package-browser-field-spec
local files should be referenced with `./`. this allows for distinction between package and local file re-mapping.

changed `"main"` as well just for consistency. doesn't really matter there.

Co-authored-by: Undefined <peizerao@gmail.com>

package.json

@@ -2,14 +2,14 @@
  "name": "ali-oss",
  "version": "6.17.0",
  "description": "aliyun oss(object storage service) node client",
- "main": "lib/client.js",
+ "main": "./lib/client.js",
  "files": [
  "lib",
  "shims",
  "dist"
  ],
  "browser": {
- "lib/client.js": "./dist/aliyun-oss-sdk.js",
+ "./lib/client.js": "./dist/aliyun-oss-sdk.js",
  "mime": "mime/lite",
  "urllib": "./shims/xhr.js",
  "utility": "./shims/utility.js",