disabled travis ci/cd in favor of github actions

.travis.yml

@@ -1,10 +0,0 @@
-language: csharp
-solution: Terminal.sln
-script:
-  - tsh_version=1.4.0-pre1
-  - msbuild /t:Restore $TRAVIS_BUILD_DIR/Terminal.sln
-  - cd $TRAVIS_BUILD_DIR/
-  - msbuild /p:Configuration=Release Terminal.sln
-mono: "6.8.0"
-dotnet: "3.1.201"
-os: "osx"