maint: Add NEWS.

* NEWS: New file.

NEWS

+                                                              -*- org -*-
+#+TITLE: Guix-Jupyter news – history of user-visible changes
+#+STARTUP: content hidestars
+
+Copyright © 2021 Ludovic Courtès <ludovic.courtes@inria.fr>
+
+  Copying and distribution of this file, with or without modification,
+  are permitted in any medium without royalty provided the copyright
+  notice and this notice are preserved.
+
+Please send bug reports to
+<https://gitlab.inria.fr/guix-hpc/guix-kernel>.
+
+
+* Changes in 0.2.0 (since 0.1.0)
+
+** New functionality
+
+*** New ‘;;guix describe’ magic command
+
+    Like the ‘guix describe’ shell command, it returns the currently-used
+    channels.
+
+*** New ‘;;guix search’ magic command
+
+    Return the list of packages matching the given patterns.
+
+*** ‘;;guix pin’ and ‘;;guix describe’ output includes links to VCS history
+
+    This allows you to see the version-control system (VCS) history
+    leading to the channel commit you’re using.
+
+*** Report build and download progress in the notebook
+
+    When Guix starts downloading or building things, for instance in
+    response to an environment creation via ‘;;guix environment’, a
+    transient line in the notebook displays what’s being built or
+    downloaded.
+
+*** Guile kernel can display SVG pictures
+
+    The built-in Guile kernel now returns SVG for images produced by
+    ‘guile-picture-language’ (see
+    https://git.elephly.net/software/guile-picture-language.git).
+
+** Bug fixes
+
+*** Gracefully handle package-not-found errors in ‘;;guix environment’
+
+*** Properly complete ‘;;guix’ magic commands
+
+*** Fix potential hang in ‘;;guix pin’
+
+*** Gracefully handle ‘;;guix download’ syntax errors
+
+** Maintenance
+
+*** Support builds with Guile 3.0 and Guile-JSON 4.5