update git URLs (git -> https; gitea)

Change-Id: I22bc1dd5c8a33fbccc8cc6d0d8daf7f558f17f44
diff --git a/debian/copyright b/debian/copyright
index b119569..79c5876 100644
--- a/debian/copyright
+++ b/debian/copyright
@@ -1,6 +1,6 @@
 Format: http://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
 Upstream-Name: libosmocore
-Source: git://git.osmocom.org/libosmocore.git
+Source: https://gitea.osmocom.org/osmocom/libosmocore
 
 Files: *
 Copyright: 2008      Daniel Willmann <daniel@totalueberwachung.de>