ci(travis): Use primary keys, not aliases; add missing key
ci(travis): Use primary keys, not aliases; add missing key

These are per Travis's new config validation report:

* root: key matrix is an alias for jobs, using jobs
* deploy: key api_key is an alias for token, using token
* root: missing os, using the default linux
* env: key matrix is an alias for jobs, using jobs

alerque/sile,alerque/sile,alerque/sile,alerque/sile