Finalize Buildpack/0.10

[natalieparellano]

@samj1912 could you please review this cumulative PR?

[natalieparellano]

I did a little clumsy dance here because (somehow) buildpack/0.10 had changes to platform.md that needed to be removed to fix the merge conflict, but you can see the changes in the end were trivial:

 narellano  narellano7JGH5  W  spec  buildpack/0.10  $  git diff e16c633 --name-only
README.md
buildpack.md
platform.md
 narellano  narellano7JGH5  W  spec  buildpack/0.10  $  git diff e16c633
diff --git a/README.md b/README.md
index 48d6060..01446eb 100644
--- a/README.md
+++ b/README.md
@@ -50,6 +50,6 @@ When the specification refers to a path in the context of an OCI layer tar (e.g.

 These documents currently specify:

-- Buildpack API: `0.9`
+- Buildpack API: `0.10`
 - Distribution API: `0.3`
-- Platform API: `0.10`
+- Platform API: `0.11`
diff --git a/buildpack.md b/buildpack.md
index c253bfb..4333a1a 100644
--- a/buildpack.md
+++ b/buildpack.md
@@ -82,7 +82,7 @@ This document specifies the interface between a lifecycle program and one or mor
     - [Build Plan (TOML) `requires.version` Key](#build-plan-toml-requiresversion-key)

 ## Buildpack API Version
-This document specifies Buildpack API version `0.9`
+This document specifies Buildpack API version `0.10`

 Buildpack API versions:
  - MUST be in form `<major>.<minor>` or `<major>`, where `<major>` is equivalent to `<major>.0`
diff --git a/platform.md b/platform.md

[natalieparellano]

Moving to draft due to some late-breaking (minor) edits