Conform every release including final and rc to semantic versioning

[mumoshu]

I'd like quit version numbers like -rc.x in favor of semantic versioning because it isn't clear which changes are included or not in the rc.

The next kube-aws release can be 0.10.1 or 0.11.0 in theory. But it would be 0.11.0 as I'm merging #1233 which is a huge change, as you can't normally just kube-aws update your clusters from previous kube-aws versions. This is discussed in #1112.

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I used to mark rc.1 to include a big feature on top of the latest final release, and the subsequent rc.2 to rc.N releases to include small features and fixes. But historically saying, any rc had been able to include breaking changes. rc.N versioning didn't differentiate such existence/inexistence of breaking change between rc's.

From another point of view, I just want to make sure every former "rc" release is considered production ready. I had been happily deploying rc's myself so from my perspective, it doesn't change anything in the quality of kube-aws releases.

[mumoshu]

kube-aws conforms to the semantic versioning in this way since v0.10.0. Closing as done.