[travis] Remove sudo: false

Travis now recommends removing `sudo: false` from configuration: https://blog.travis-ci.com/2018-11-19-required-linux-infrastructure-migration.

diff --git a/.travis.yml b/.travis.yml
index 79287ccf68630d8b669d8b646e9bd50b5117689c..82e81d0785ab7d9f9e6d253228a765a41c39f7d2 100644 (file)
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,7 +9,6 @@ python:
   - "3.6"
   - "pypy"
   - "pypy3"
-sudo: false
 env:
   - YTDL_TEST_SET=core
   - YTDL_TEST_SET=download