Update all `secret: ` values in `.travis.yml`

[🇺🇦 Sviatoslav Sydorenko (Святослав Сидоренко)]

Do like this:

REPO_NAME={{ YOUR_REPO_NAME }}
travis encrypt -r "aio-libs/${REPO_NAME}" --api-endpoint 'https://api.travis-ci.com/'

Ref: https://github.com/orgs/aio-libs/teams/admins/discussions/9

[Andrew Svetlov]

Fixed by 83914af