YIN parser CHANGE simplify copying of the tested string

parsed revision date is checked and its copying into a constant-size
buffer can be simplified by memcpy().
diff --git a/src/parser_yin.c b/src/parser_yin.c
index 6bbeb9b..ef0c65e 100644
--- a/src/parser_yin.c
+++ b/src/parser_yin.c
@@ -1711,7 +1711,7 @@
         FREE_STRING(ctx->xmlctx->ctx, temp_date);
         return LY_EVALID;
     }
-    strncpy(rev->date, temp_date, LY_REV_SIZE);
+    memcpy(rev->date, temp_date, LY_REV_SIZE);
     FREE_STRING(ctx->xmlctx->ctx, temp_date);
 
     /* parse content */