Update podspec version and added description to changelog (openid#763)

Prep for 1.6.0 release (openid#722)

* Reformat changelog.

* Update changelog for 1.6.0 release.

* Bump the podspec version for the 1.6.0 release.

Prepare for 1.5.0 release (openid#692)

* Bump podspec version for 1.5.0 release.

* Update changelog for 1.5.0 release.

Added changelog for 1.4.0

Version 1.3.0

- Support for Mac Catalyst

Version 1.2.0

- iOS 13 support

1.1.0 release

1.0.0 release

0.95.1 release