ci: remove travis spec

.travis.yml

@@ -1,28 +0,0 @@
-version: ~> 1.0
-import: nix-community/nix-travis-ci:nix.yml@main
-
-dist: xenial
-os: linux
-
-env:
-  global:
-    - CACHIX_CACHE="xeals"
-    - NUR_REPO="xeals"
-
-jobs:
-  include:
-    - env: NIX_PATH=nixpkgs=channel:nixpkgs-unstable
-    - env: NIX_PATH=nixpkgs=channel:nixos-unstable
-    # - env: NIX_PATH=nixpkgs=channel:nixos-20.03
-
-script:
- - nix-build ci.nix -kA buildOutputs
- - nix eval -f default.nix 'lib'
- - nix eval -f default.nix 'modules'
- - nix eval -f default.nix 'overlays'
-
-after_success:
-  - if [ -n "${CACHIX_CACHE}" ]; then nix-build ci.nix -kA cacheOutputs | cachix push "${CACHIX_CACHE}"; fi
-  - if [[ NUR_REPO != "xeals" && "cron" != "${TRAVIS_EVENT_TYPE}" && "false" = "${TRAVIS_PULL_REQUEST}" && "master" = "${TRAVIS_BRANCH}" ]]; then
-      curl -XPOST "https://nur-update.herokuapp.com/update?repo=${NUR_REPO}"; fi
-