feat: add code coverage report GitHub Action

Fix devfile#929

Signed-off-by: Andrew Obuchowicz <[email protected]>

Author: AObuchow

.github/workflows/code-coverage.yml

@@ -1,4 +1,4 @@
-name: Check Code Coverage
+name: Code Coverage Report
 
 on:
   push:

README.md

@@ -1,5 +1,7 @@
 # Dev Workspace Operator
 
+[![codecov](https://codecov.io/gh/devfile/devworkspace-operator/branch/main/graph/badge.svg)](https://codecov.io/gh//devfile/devworkspace-operator)
+
 Dev Workspace operator repository that contains the controller for the DevWorkspace Custom Resource. The Kubernetes API of the DevWorkspace is defined in the https://github.com/devfile/api repository.
 
 ## DevWorkspace CR
@@ -181,3 +183,5 @@ This will delete all custom resource definitions created for the controller, as
 #### GitHub actions
 
 - [Next Dockerimage](https://github.com/devfile/devworkspace-operator/blob/main/.github/workflows/dockerimage-next.yml) action builds main branch and pushes it to [quay.io/devfile/devworkspace-controller:next](https://quay.io/repository/devfile/devworkspace-controller?tag=latest&tab=tags)
+
+- [Code Coverage Report](./.github/workflows/code-coverage.yml) action creates a code coverage report using [codecov.io](https://about.codecov.io/).