docs: Update copyright year range.

c4b9f30a · Oliver Galvin · Guido Gunther · 7c50c151 · c4b9f30a
Commit c4b9f30a authored Jun 15, 2019 by Oliver Galvin Committed by Guido Gunther Dec 09, 2019
--- a/doc/handy-docs.xml
+++ b/doc/handy-docs.xml
@@ -21,7 +21,7 @@
    </releaseinfo>

    <copyright>
-      <year>2017-2018</year>
+      <year>2017-2019</year>
      <holder>Purism SPC</holder>
    </copyright>
  </bookinfo>