Version 1.8.10 was released and updated in the package but due to not going through the proper packaging process for a rename it doesn't actually build in koji.

From the spec commit:
# With version 1.8.10, the upstream pycairo project began releasing multiple
# tarballs for different Python versions: py2cairo for Python 2, and pycairo
# for Python 3.  In order to provide a smooth upgrade path for users wishing
# to stay on the Python 2 version, this package was renamed to python-cairo
# and a python3-cairo package was introduced for Python 3.

The process to do this properly is listed here
http://fedoraproject.org/wiki/Upgrade_paths_%E2%80%94_renaming_or_splitting_packages