fix: add missing curl extension requirement

chore: add phpunit cache to .gitignore

Merge pull request php-opencloud#331 from alcalyn/patch-1

Fix Call to undefined function GuzzleHttp\Psr7\modify_request()

Added support for PHP 8.0

Guzzle 7 and minor improvements

Merge pull request php-opencloud#296 from php-opencloud/travis

Travis

Merge pull request php-opencloud#255 from biigle/fix-large-object-seg…

…ments

Fix number of segments of a large object

Merge pull request php-opencloud#228 from php-opencloud/backport

Bumped dependencies to remove guzzle/guzzle

Readme (php-opencloud#227)

* Use coveralls badge. Fixed typo.

* Clarify roadmap and support

Backport: Serialize \ DateTimeImmutable (php-opencloud#220)