Add dep5 file to handle test data

dep5 is a format developed for Debian and supported by REUSE spec and
tooling.

Its goal is to give ability to license files that do not support license
headers that are both human- and machine-readable.

Currently test certs and expected yamls are handled here.

Signed-off-by: Alexander Mazuruk <aalexanderr@gmail.com>

.reuse/dep5

@@ -0,0 +1,30 @@
+Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
+Upstream-Name: Matter
+Upstream-Contact: Jane Doe <jane@example.com>
+Source: https://github.com/project-chip/connectedhomeip
+
+Files:
+  credentials/**/*.pem
+License: Apache-2.0
+Copyright: Project CHIP Authors
+
+Files:
+  credentials/**/*.der
+License: Apache-2.0
+Copyright: Project CHIP Authors
+
+Files:
+  credentials/**/*.json
+License: Apache-2.0
+Copyright: Project CHIP Authors
+
+Files:
+  credentials/**/*.chip
+License: Apache-2.0
+Copyright: Project CHIP Authors
+
+Files:
+  credentials/**/*.chip-b64
+License: Apache-2.0
+Copyright: Project CHIP Authors
+