Delete .travis.yml

.travis.yml

-language: julia
-os:
-  - osx
-  - linux
-  - windows  
-julia:
-  - 1.4
-beofre_script:
-  - julia -e 'using Pkg; Pkg.add(PackageSpec(url="https://github.com/mathn7/TestOptinum.git"))'
-
-notifications:
-  email: false
-  
-jobs:
-  include:
-    - stage: Documentation
-      julia: 1.4
-      os: linux
-      script:        
-        - julia --project=docs -e 'using Pkg; Pkg.instantiate(); Pkg.develop(PackageSpec(path=pwd()))'        
-        - julia --project=docs --color=yes docs/make.jl
-      after_success: skip