Drop EVM in favor of nix-emacs-ci

.travis.yml

@@ -1,25 +1,24 @@
-language: rust
-dist: trusty
+language: nix
+env:
+  - EMACS_CI=emacs-25-1
+  - EMACS_CI=emacs-25-3
+  - EMACS_CI=emacs-26-1
+  - EMACS_CI=emacs-26-3
 before_install:
-  # evm
-  - git clone https://github.com/rejeep/evm.git $HOME/.evm
-  - export PATH=$HOME/.evm/bin:$PATH
-  - evm config path /tmp
-  - evm install $EVM_EMACS --use --skip
+  # nix-emacs-ci
+  - bash <(curl https://raw.githubusercontent.com/purcell/nix-emacs-ci/master/travis-install)
 
   # cask
-  - curl -fsSkL https://raw.github.com/dajva/cask/master/go | python
+  - curl -fsSkL https://raw.github.com/cask/cask/master/go | python
   - export PATH=$HOME/.cask/bin:$PATH
   - cask
 
+  # rust
+  - curl https://sh.rustup.rs -sSf | sh -s -- -y
+  - source $HOME/.cargo/env
+
   # ripgrep
   - cargo install ripgrep
-  - export PATH=$HOME/.cargo/bin:$PATH
-env:
-  - EVM_EMACS=emacs-25.1-travis
-  - EVM_EMACS=emacs-25.3-travis
-  - EVM_EMACS=emacs-26.1-travis
-  - EVM_EMACS=emacs-26.2-travis
 install:
   - make deps
 script: