chore(ci): remove travis.yml

.travis.yml

@@ -1,21 +0,0 @@
-language: rust
-cache: cargo
-dist: trusty
-os:
-  - linux
-  - osx
-
-rust:
-  - nightly
-  - stable
-
-before_script:
-  - rustup component add rustfmt
-  - cargo install --force cargo-audit
-  - cargo generate-lockfile
-
-script:
-  - cargo fmt --all -- --check
-  - cargo build
-  - cargo test
-  - cargo audit