Add missing "body-parser" dependency.

[ferhtgoldaraz]

There's a use of a dependency (body-parser) that's used but not declared. It will only work if it's also a dependency of a adependency, but it can change or break unpredictably.

Use in the code:
https://github.com/stil4m/elm-analyse/blob/c4b07bc/ts/server/app.ts

The dependeny tree, as seen with npm ls body-parser:

myproject@1.0.0 /Users/someone/src/myproject
└─┬ elm-analyse@0.16.1
  ├─┬ express@4.16.3
  │ └── body-parser@1.18.2
  └─┬ express-ws@/express-ws/2.0.0/express@4.16.3
    └─┬ express@4.16.3
      └── body-parser@1.18.2

Info about this kind of phantom dependencies: https://rushjs.io/pages/advanced/phantom_deps/

[ferhtgoldaraz]

Pull request that fixes it
#192

[ferhtgoldaraz]

merged!