patch 8.2.0481: Travis is still using trusty

Problem:    Travis is still using trusty.
Solution:   Adjust config to use bionic. (Ozaki Kiichi, closes #5868)
diff --git a/src/testdir/lsan-suppress.txt b/src/testdir/lsan-suppress.txt
index 5166fbf..a3008bd 100644
--- a/src/testdir/lsan-suppress.txt
+++ b/src/testdir/lsan-suppress.txt
@@ -1,3 +1,11 @@
-# Suppress leaks from X libraries on Ubuntu trusty.
+# Suppress leaks from X libraries on Ubuntu bionic.
 leak:libX11.so.6
 leak:libXt.so.6
+leak:libcairo.so.2
+leak:libfontconfig.so.1
+leak:libglib-2.0.so.0
+leak:libtinfo.so.5
+# Suppress leaks from other language libraries.
+leak:libperl.so.*
+leak:libpython*.so.*
+leak:libruby*.so.*
diff --git a/src/version.c b/src/version.c
index e09cf4f..4288be7 100644
--- a/src/version.c
+++ b/src/version.c
@@ -739,6 +739,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    481,
+/**/
     480,
 /**/
     479,