[plugin-express] use proper TypeScript namespace importing for express

[KevinLiddle]

My project is using express and bugsnag and I've been upgrading my typescript, express, bugsnag, and other dependencies. After making the necessary changes to my code, I get the following error from plugin-express/types/bugsnag-express.d.ts:

node_modules/@bugsnag/plugin-express/types/bugsnag-express.d.ts:2:8 - error TS1259: Module '"<path to project>/node_modules/@types/express/index"' can only be default-imported using the 'esModuleInterop' flag

2 import express from 'express'
         ~~~~~~~

  node_modules/@types/express/index.d.ts:116:1
    116 export = e;
        ~~~~~~~~~~~
    This module is declared with using 'export =', and can only be used with a default import when using the 'esModuleInterop' flag.

Using the esModuleInterop config option breaks several other of my dependencies, but changing the import to a proper typescript namespace import fixes my issues and I'm able to build again. I don't believe this would be a breaking change for any setup.

[KevinLiddle]

travis failed because of:

The DANGER_GITHUB_API_TOKEN/DANGER_BITBUCKETSERVER_HOST/DANGER_GITLAB_API_TOKEN environmental variable is missing
Without an api token, danger will be unable to comment on a PR
Error:  Error: Cannot use authenticated API requests.

Not sure what I can do about that.

[mattdyoung]

Hi @KevinLiddle

Thanks for the PR. We think the change makes sense but we'll need to perform some more testing to confirm there are no other side effects. We'll take a look at this when priorities allow.

Thanks!

[bengourley]

I've tested this and see no problems. Going to ship the fix in a patch release today. Thanks @KevinLiddle for your contribution 🥂

[KevinLiddle]

🥳 thanks @bengourley and @mattdyoung!