symfony/dom-crawler upgrade

Last upgrade needed: symfony/dom-crawler

Package updates

Updated Carbon to a newer version and fixed a couple of deprecation warnings as well as PHP 7.3 incompatibilities.

Also now testing for PHP 7.3 and PHP 7.4 in TravisCI

Drop Arxiv version

Arxiv identifiers can look like:

• 1609.05197
• 1609.05197v2

They both link to the same API metadata with the latest version up to date. Keeping the latest version is not ideal as it makes it harder to look for.

Default to first day of month update

0.2.16

Default to first day of month update

Fix introduced bug

0.2.15

Fix intruduced bug

Better Update Types

0.2.14

Better Update type standarisation

Catch as many emails as possible

0.2.13

Change Email regex for a more catch all version

Use secure DOI API URL

Thanks to @katrinleinweber for this update!

Fix Arxiv author list bug

Arxiv extractor was only listing the first author. Welcome to the PHP XML Hell 😄

Author attribute setter refactor

Try to get rated 10 by Scrutinizer 😄