Fix installation failure due to MarkupSafe and setuptools version conflict

[amironoff]

Hi @fliot! Here's a small MarkupSafe-related bugfix:

Context

Deployment from filot/ScrapyKeeper master branch would fail on Docker running inside Windows 10 because of MarkupSafe==1.0 requirement. It's incompatible with setuptools newer than v.46 (see https://github.com/pallets/markupsafe/issues/116).

Changes

Upgraded MarkupSafe to 1.1.1 and upgraded the rest of dependencies to latest version.

Testing

Deployed ScrapyKeeper to Alpine Linux docker containers, hosted on Ubuntu 18.0.4 and Windows 10 machines, deployed a scrapyd egg, ran a smoke test crawl. Looks like everything's working and upgrading didn't break anything.