add change statement: authorship, dates to LGPL v2.1 files

lib/raop_buffer.c

@@ -10,6 +10,9 @@
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  *  Lesser General Public License for more details.
+ *
+ *==================================================================
+ * modified by fduncanh 2021-2023
  */
 
 #include <stdlib.h>