Update README.md

deprecation warning

README.md

@@ -1,3 +1,9 @@
+## :warning: Deprecation warning
+
+On Oct 1, 2020 this repository, including issues and pull requests, will be archived and transferred to [gitlab.com](https://gitlab.com/kicad/libraries/kicad-packages3D-source/). In order for your pull requests and issues to be imported into GitLab you must set your email address on GitHub to public and use the same address for your GitLab account. Or login to GitLab at least once using the GitHub icon. Otherwise the importer can't correlate the account information and the issues/comments on GitLab will be owned by `kicad-bot` ([importer documentation](https://docs.gitlab.com/ee/user/project/import/github.html#how-it-works)).
+
+---
+
 # kicad-packages3D-source
 
 This repository contains source files for the 3D models found at https://github.com/KiCad/kicad-packages3d
@@ -9,4 +15,4 @@ These source files can be in the form of:
 
 Please note that there will be preference for scripted and free open source program generated models due to maintenance reasons.
 
-Also, even though models produced with proprietary software are accepted, the final file export should be made in FreeCAD using StepUp.
+Also, even though models produced with proprietary software are accepted, the final file export should be made in FreeCAD using StepUp.