Potential fix for issue #1772.
Instead of comparing string literals for versions we compare Pod::Version objects, which does a better job at comparing version numbers with double-digit parts (such as 1.9.10 and 1.10.10).
This is my first contribution to CocoaPods so do not hesitate to let me know if there is anything wrong. :-)
determine the highest known specification by using Pod::Version#<=>
Oh, can you please add a CHANGELOG entry crediting yourself?