Cleanup Travis config (#262)
Cleanup Travis config (#262)

Travis YAML cleanup

Removes warnings in Travis v2 config validation:

 root: duplicate key: addons
 deploy: deprecated key skip_cleanup (not supported in dpl v2, use cleanup)
 deploy: deprecated key skip_cleanup (not supported in dpl v2, use cleanup)
 addons.snaps: unknown key confinement (classic)
 deploy: key github_token is an alias for token, using token
 deploy: key api_key is an alias for token, using token

Changes:

- remove duplicate 'addons' key
- replace 'github_token' with 'token' in deploy.provider:"pages"
- replace 'api_key' with 'token' in deploy.provider:"release"
- replace 'skip_cleanup:true' with 'cleanup:false' in deploy.provider.*
- replace 'confinement:classic' with 'classic:true' in addons.snaps[0]

Ref:
- https://docs.travis-ci.com/user/deployment-v2/providers/pages/
- https://docs.travis-ci.com/user/deployment-v2/providers/releases/
- https://config.travis-ci.com/ref/job/addons/snaps

kopia/kopia,kopia/kopia,kopia/kopia,kopia/kopia