Remove Travis configuration and update build action to use v2 of checkout

.github/workflows/build.yml

@@ -16,7 +16,7 @@ jobs:
         environment: ['Debug', 'Release', 'Profile Debug', 'Profile Release']
     name: ${{ matrix.environment }} build (Dotnet ${{ matrix.dotnet }}, OS ${{ matrix.os }})
     steps:
-      - uses: actions/checkout@master
+      - uses: actions/checkout@v2
       - name: Setup dotnet
         uses: actions/setup-dotnet@v1
         with:

.travis.yml

@@ -1,9 +0,0 @@
-os: osx
-language: csharp
-solution: Ryujinx.sln
-mono: none
-dotnet: 2.0.0
-script:
- - dotnet restore
- - dotnet build
- - cd Ryujinx.Tests && dotnet test