Prepare release 6.0.12. (#148)

Author: mauritsvanrees

README.md

@@ -27,7 +27,7 @@ These images are **not** Buildout based!
 
 | Plone Version | Tags | Dockerfile |
 | --- | --- | --- |
-| 6 | `6.0.11.1`, `6.0`, `6`, `latest` | [(6.0.x/Dockerfile)](https://github.com/plone/plone-backend/blob/v6.0.11.1/Dockerfile)|
+| 6 | `6.0.12`, `6.0`, `6`, `latest` | [(6.0.x/Dockerfile)](https://github.com/plone/plone-backend/blob/v6.0.12/Dockerfile)|
 | 6 (nightly) | `nightly` |  [(Dockerfile.nightly)](https://github.com/plone/plone-backend/blob/6.0.x/Dockerfile.nightly) |
 
 ### Unsupported tags

version.txt

@@ -1 +1 @@
-6.0.11.1
+6.0.12