Exclude errors from ESearchResults

The result of the ESearchResults API can include an "errorlist" array, in which case we should not read the Pubmed ID

Fetch complementary resources

Try to fix the bug where we don't get data from complementary resources such as PubMed

Stop calling doi.org

We've experienced some performance issues when calling doi.org API.

Fix guzzle Exception error

0.6.2

Apply fixes from StyleCI (#26)

update Carbon

update Carbon

guzzle-factory update

guzzle-factory update

PHP 8 and higher

Allow for PHP 8 and higher

Fetch complementary resources bug

There is a bug in the complementary resources fetch process.

Resolve Carbon conflict

0.4.2

Didn't like Carbon update on an old version of Laravel

Preprint data

Add a link key on the generated JSON to reflect the publication's link to a preprint. Two values are possible:

• is_preprint_of
• has_preprint