[TEP-0012]: Mark as implemented

Tekton now has an API spec and conformance tests for TaskRun.
We may want to add conformance docs and tests for other parts of the Tekton API,
but the foundation has been laid for adding these later,
and this work can be tracked through Github issues instead of leaving this TEP open.

teps/0012-api-spec.md

@@ -3,8 +3,8 @@ title: API Specification
 authors:
   - "@imjasonh"
 creation-date: 2020-08-10
-last-updated: 2020-08-10
-status: implementable
+last-updated: 2021-12-14
+status: implemented
 ---
 
 # TEP-0012: Tekton Pipelines API Spec
@@ -24,6 +24,7 @@ status: implementable
 - [Test Plan](#test-plan)
 - [Drawbacks](#drawbacks)
 - [Alternatives](#alternatives)
+- [Implementing PRs](#implementing-prs)
 - [References (optional)](#references-optional)
 <!-- /toc -->
 
@@ -109,6 +110,10 @@ We could continue to build and grow Tekton without an API spec.
 
 Without a documented API spec, [Hyrum's Law](https://www.hyrumslaw.com) dictates that _any_ observable behavior of an implementation will eventually come to be depended upon by users, and thus any observable behavior of an implementation effectively becomes its de facto spec. Indeed, this can happen even _with_ an API spec, but by at least attempting to delineate supported features, we can hopefully delay the inevitable.
 
+## Implementing PRs
+- [Tekton API Spec](https://github.com/tektoncd/pipeline/pull/3131)
+- [TaskRun conformance tests](https://github.com/tektoncd/pipeline/pull/3400)
+
 ## References (optional)
 
 * [Original API Spec Proposal Doc](https://docs.google.com/document/d/1bWPMCKng7dJu6MRj0GmaSqU61YpSjr9HrTlK-nAHJ3Q/edit) (from November 2019)

teps/README.md

@@ -169,7 +169,7 @@ This is the complete list of Tekton teps:
 |[TEP-0009](0009-trigger-crd.md) | Trigger CRD | implementable | 2020-09-08 |
 |[TEP-0010](0010-optional-workspaces.md) | Optional Workspaces | implemented | 2020-10-15 |
 |[TEP-0011](0011-redirecting-step-output-streams.md) | redirecting-step-output-streams | implementable | 2020-11-02 |
-|[TEP-0012](0012-api-spec.md) | API Specification | implementable | 2020-08-10 |
+|[TEP-0012](0012-api-spec.md) | API Specification | implemented | 2021-12-14 |
 |[TEP-0014](0014-step-timeout.md) | Step Timeout | implemented | 2021-12-13 |
 |[TEP-0015](0015-pending-pipeline.md) | pending-pipeline-run | implemented | 2020-09-10 |
 |[TEP-0016](0016-concise-trigger-bindings.md) | Concise Embedded TriggerBindings | implemented | 2020-09-15 |