remove unused travis file

.travis.yml

-language: node_js
-os: linux
-sudo: required
-dist: trusty
-before_install:
-  - sudo apt-get install -y mesa-utils
-  - sudo apt-get install -y xvfb
-  - sudo apt-get install -y libgl1-mesa-dri
-  - sudo apt-get install -y libglapi-mesa
-  - sudo apt-get install -y libosmesa6
-  - sudo apt-get install -y gcc-4.9
-  - sudo apt-get install -y libstdc++6
-  - sudo apt-get install -y libxi-dev
-node_js:
-  - "12"
-  - "10"
-before_script:
-  - export DISPLAY=:99.0; sh -e /etc/init.d/xvfb start
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