ctucx.git: dns.nix

Move licensing information of README.md to the file itself

The wording in the REUSE specification indicates that is preferrable for
the licensing information to be present either on the file itself or in
an adjacent .license file, and that the dep5 file be left for licensing
files and directories in bulk.

diff --git a/.reuse/dep5 b/.reuse/dep5
@@ -1,5 +0,0 @@
-Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
-
-Files: README.md
-Copyright: © 2019 Kirill Elagin <kirelagin@gmail.com>
-License: MIT

diff --git a/README.md b/README.md
@@ -1,3 +1,9 @@
+<!--
+SPDX-FileCopyrightText: 2020 Kirill Elagin <kirelagin@gmail.com>
+
+SPDX-License-Identifier: MIT
+-->
+
 _Nix DSL for defining DNS zones_
 
 nix-dns

diff --git a/flake.lock.license b/flake.lock.license
@@ -1,2 +1,3 @@
 SPDX-FileCopyrightText: 2020 Kirill Elagin <kirelagin@gmail.com>
+
 SPDX-License-Identifier: CC0-1.0