NEWS: add v12 entry

Add a NEWS entry for all major changes since v11, but exclude anything
not relevant to packagers and users.

NEWS.md

@@ -1,5 +1,59 @@
 # OSBuild - Build-Pipelines for Operating System Artifacts
 
+## CHANGES WITH 12:
+
+        * The `qemu` assembler now supports the `VHDX` image format. This is the
+          preferred format for AWS targets, so it is a natural fit for our
+          assemblers.
+
+        * The `grub2` stage now disables the legacy compatibility by default.
+          You have to explicitly enable it in the stage options if you require
+          it.
+
+        * Additionally, the `grub2` stage now also has a `uefi.install` option
+          to control whether it installs the UEFI configuration from the build
+          tree into the target tree. Furthermore, a new option called
+          `write_defaults` controls whether default options are written to
+          `/etc` (enabled by default).
+
+        * The `dnf` stage was removed. The `rpm` stage fully replaces all its
+          functionality.
+
+        * The `fedora27` runner is no longer supported. Fedora 30 is the minimum
+          required host version for Fedora systems.
+
+        * Add OSTree integration. This includes multiple stages and sources
+          which allow to export osbuild trees as ostree commits, or import
+          ostree commits into an osbuild pipeline:
+
+            * org.osbuild.rpm-ostree: This stage uses `rpm-ostree compose` to
+                                      post-process a tree and prepare it for
+                                      committing to ostree.
+
+            * org.osbuild.ostree.commit: A new assembler that takes a tree that
+                                         conforms to the ostree layout and
+                                         turns it into an ostree commit.
+
+            * org.osbuild.ostree: A new source that provides external ostree
+                                  commits to a pipeline.
+
+            * org.osbuild.ostree: A new stage that takes an ostree commit and
+                                  prepares the working directory with its
+                                  content.
+
+        * The `osbuild` binary now has an `--output-directory=DIR` argument
+          which allows to specify a directory where to put the output of the
+          pipeline assembler. This is optional for now, but will be made
+          mandatory in the future.
+
+        * A new stage called `org.osbuild.first-boot` allows to control the
+          execution of scripts at the first bootup of the generated images.
+
+        Contributions from: Christian Kellner, David Rheinsberg, Major Hayden,
+                            Ondřej Budai, Tom Gundersen
+
+        - Berlin, 2020-04-15
+
 ## CHANGES WITH 11:
 
         * Drop support for legacy input: passing in non-manifest style