travis.yml: Fix Travis YAML configuration warnings

This fixes the following warnings Travis has detected on the
YAML configuration:

- 'on root: missing os, using the default "linux"'
- 'on root: the key matrix is an alias for jobs, using jobs'
- 'on jobs.include.python: unexpected sequence, using the first value (3.5)'
- 'on jobs.include.python: unexpected sequence, using the first value (3.6)'

Signed-off-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200207210124.141119-2-wainersm@redhat.com>
Message-Id: <20200225124710.14152-7-alex.bennee@linaro.org>
1 file changed