Upgrade library versions for compatibility with JupyterLab 2.0

[jhelie]

I'm not sure this is the correct way of bumping jupytext but with these changes the extension works again with JupyterLab 2.0.

[jhelie]

Thanks, I've tried addressing these (and updating setup.py so that Travis tests work) but I can't seem to be able to build locally as jlpm install fails with:

> [email protected] build /home/jean/repos/projects/jupytext/packages/labextension
> tsc

node_modules/@jupyterlab/ui-components/lib/icon/labicon.d.ts:3:8 - error TS1259: Module '"/home/jean/repos/projects/jupytext/packages/labextension/node_modules/@types/react/index"' can only be default-imported using the 'esModuleInterop' flag

3 import React from 'react';
         ~~~~~

  node_modules/@types/react/index.d.ts:62:1
    62 export = React;
       ~~~~~~~~~~~~~~~
    This module is declared with using 'export =', and can only be used with a default import when using the 'esModuleInterop' flag.

src/index.ts:7:10 - error TS2305: Module '"../node_modules/@jupyterlab/coreutils/lib"' has no exported member 'nbformat'.

7 import { nbformat } from "@jupyterlab/coreutils";
           ~~~~~~~~

I'm not sure what change on my end triggers this new error.

[jhelie]

I think I found the two issues:

• nbformat now has its own package (was actually mentioned in the migration guide)
• esModuleInterop had to be set to true in tsconfig.json

[codecov]

Codecov Report

Merging #449 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master     #449   +/-   ##
=======================================
  Coverage   98.91%   98.91%           
=======================================
  Files          77       77           
  Lines        7573     7573           
=======================================
  Hits         7491     7491           
  Misses         82       82

Impacted Files	Coverage Δ
jupytext/version.py	100% <100%> (ø)	⬆️

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[mwouts]

Jean, I have documented the change in the CHANGELOG, and added a word about how to use the previous version of the extension with JupyterLab 1.x. in the README for the extension. Is that OK with you?

Many thanks again for your contribution!

[jhelie]

Just fixed a typo in the PR reference but otherwise LGTM, thanks! Happy for this to be merged whenever.

[mwouts]

Excellent ! Thank you @jhelie !