update dependencies

Merge pull request #2 from finn0/cumulative-update

Cumulative update

Add remainder of EPushType types (sideshow#153)

* Add remainder of EPushType types

Support for testing golang 1.13.x (sideshow#147)

Change push-type tests for better coverage (sideshow#144)

Remove support for go 1.6 (sideshow#142)

Removes support for golang 1.6 so we can better support new features
moving forward

Support for testing golang 1.12.x (sideshow#130)

Add support for Summary arguments in notifications for iOS 12 (sidesh…

…ow#119)

* Add summary-arg

Allow PKCS#8 private keys in .pem files (sideshow#101)

* Allow PKCS#8 private keys in .pem files

* Fix tests and test new behavior