fix: wrong checkout command in documentation (#894)

Signed-off-by: Pasha Kostohrys <[email protected]>
Signed-off-by: Tchoupinax <[email protected]>

Author: pasha-codefresh

docs/contributing/releasing.md

@@ -17,7 +17,7 @@ Then create a release branch:
 
 ```
 git clone [email protected]:argoproj-labs/argocd-image-updater.git
-git branch -b release-0.13
+git checkout -b release-0.13
 git push origin release-0.13
 ```