Remove Travis and use Github Actions

.github/workflows/dotnetcore.yml

@@ -0,0 +1,31 @@
+name: .NET Core
+
+on: [push]
+
+jobs:
+  test:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Chectout
+      uses: actions/checkout@v1
+    - name: Setup .NET Core
+      uses: actions/setup-dotnet@v1
+      with:
+        dotnet-version: 3.0.100
+    - name: Build with dotnet
+      run: dotnet build --configuration Release
+    - name: Check format
+      run: |
+        dotnet tool install --tool-path ./ dotnet-format
+        ./dotnet-format --check --dry-run -v diagnostic
+    - name: Test
+      run: |
+        find tests -name *.csproj | xargs -I % dotnet add % package coverlet.msbuild
+        dotnet test /p:CollectCoverage=true /p:CoverletOutputFormat=lcov
+    - name: Coveralls
+      uses: coverallsapp/github-action@master
+      with:
+        github-token: ${{ secrets.GITHUB_TOKEN }}
+        path-to-lcov: ./tests/neo-vm.Tests/coverage.info