Release 1.1.0

Merge pull request #19 from stof/patch-1

Fix the min version for client-common

Merge pull request #15 from danalloway/danalloway-provide-async

provide async implementation

Merge pull request #12 from php-http/dev-discovery10

Using discovery 1.0

Merge pull request #11 from php-http/Nyholm-patch-1

Using latest version of discovery

Merge pull request #10 from php-http/updates

Update dependencies, remove puli requirement, add unit tests

Prepare release

Allow newer php-http/discovery versions

Add client-common dependency