Move the TaskRun use case to non-goals ⚽

In the review @vdemeester pointed out that it feels like we are trying
to deal with 2 different things - for me the main reason for that is b/c
I have a feeling we WILL solve @mattmoor 's use case - since we'll
probably have to change TaskRuns to make it happen - but I agree with
@vdemeester that that's not the main thing we're targetting here.

Now TEP-0044 is more aligned with TEP-0046 than ever!

teps/0044-composing-tasks-with-tasks.md

@@ -44,9 +44,11 @@ Some problems with this:
 * PVCs add additional overhead, both in speed and in management (somewhat
   mitigated by
   [letting tekton create and delete volumes for you](https://github.com/tektoncd/pipeline/blob/master/docs/workspaces.md#volumeclaimtemplate)
-* Sometimes you just want to run a Task with a teeny bit more functionality,
-  e.g. you want to use a task to build images, but you want to clone source
-  with git first, and it seems like overkill to have to construct a pipeline
+  but the PVCs still slow down the overall execution.
+  * Sometimes you just want to run a Task with a teeny bit more functionality,
+    e.g. you want to use a task to build images, but you want to clone source
+    with git first, and it seems like overkill to have to construct a pipeline
+    deal with persistent volume claims
 
 ### PipelineResources
 
@@ -90,6 +92,13 @@ Issues that don't let PipelineResources (as is) solve these problems are:
 - Completely replacing PipelineResources: we could decide to solve this by improving PipelineResources,
   or we could add a new feature via this TEP and still continue to support PipelineResources
   (since they provide [more functionality than just composition](https://docs.google.com/document/d/1KpVyWi-etX00J3hIz_9HlbaNNEyuzP6S986Wjhl3ZnA/edit#))
+- This was previously a use case we were targetting but we've decided to descope the TEP slightly,
+  though if we end up solving this problem as well, that's a bonus:
+  * A user wants to use a Task from the catalog with a git repo and doesn't want the extra
+    overhead of using a Pipeline, they just want to make a TaskRun,
+    e.g. [@mattmoor's feedback on PipelineResources and the Pipeline beta](https://twitter.com/mattomata/status/1251378751515922432))
+    where he wants to checkout some code and [use the kaniko task](https://github.com/tektoncd/catalog/tree/master/task/kaniko/0.1)
+    without having to fiddle with volumes
 
 ### Use Cases (optional)
 
@@ -99,11 +108,6 @@ Issues that don't let PipelineResources (as is) solve these problems are:
   cloning with [git-clone](https://github.com/tektoncd/catalog/tree/master/task/git-clone/0.2),
   running tests with [golang-test](https://github.com/tektoncd/catalog/tree/master/task/golang-test/0.1)
   and uploading results with [gcs-upload](https://github.com/tektoncd/catalog/tree/master/task/gcs-upload/0.1).
-- A user wants to use a Task from the catalog with a git repo and doesn't want the extra
-  overhead of using a Pipeline, they just want to make a TaskRun,
-  e.g. [@mattmoor's feedback on PipelineResources and the Pipeline beta](https://twitter.com/mattomata/status/1251378751515922432))
-  where he wants to checkout some code and [use the kaniko task](https://github.com/tektoncd/catalog/tree/master/task/kaniko/0.1)
-  without having to fiddle with volumes
 - An organziation does not want to use PVCs at all; for example perhaps they have decided
   on uploading to and downloading from buckets in the cloud (e.g. GCS)
 - An organization is willing to use PVCs to some extent but needs to put limits on their use