Fix docker: invalid reference format (#767)

* Fix local Docker actions: invalid reference format

* Create Dockerfile

* Create Dockerfile

* Update push.yml

* Revert "Create Dockerfile"

This reverts commit 9d1dbbc2c7fdf52963e55feb4148ac2b14d639d0.

* Fix lint

* fix: re-use image that is already present in repo

ubuntu:latest would pull unnecessary blobs from registry and count toward API limit

* fix: revert change

reverting due to issue in image deletion that will have to be investigated separately

Co-authored-by: Ryan <me@hackerc.at>

pkg/runner/testdata/local-action-dockerfile/push.yml

@@ -9,3 +9,4 @@ jobs:
     - uses: ./actions/docker-local
       with:
         who-to-greet: 'Mona the Octocat'
+    - uses: ./localdockerimagetest_

pkg/runner/testdata/localdockerimagetest_/Dockerfile

@@ -0,0 +1,2 @@
+FROM ubuntu:latest
+CMD echo Hello