Merge pull request #325 from buildpacks/platform/0.10

Finalize platform/0.10

Author: Natalie Arellano

README.md

@@ -52,4 +52,4 @@ These documents currently specify:
 
 - Buildpack API: `0.8`
 - Distribution API: `0.3`
-- Platform API: `0.9`
+- Platform API: `0.10`