chore: Add Samuel Debionne to maintainers

Samuel (https://github.com/sdebionne, @sdebionne) has been an active
contributor and maintainer with commit access for several years now.
This change corrects an obvious oversight.

Signed-off-by: Mateusz Łoskot <mateusz@loskot.net>

Author: mloskot

meta/libraries.json

@@ -15,6 +15,7 @@
         "Iterators"
     ],
     "maintainers": [
+        "Samuel Debionne",
         "Pranam Lashkari <plashkari628 -at- gmail.com>",
         "Mateusz Loskot <mateusz -at- loskot.net>",
         "Stefan Seefeld <stefan -at- seefeld.name>"