Merge pull request #5 from jernejk/upgrade-travis-build

Update .travis.yml

Author: jernejk

.travis.yml

@@ -2,10 +2,10 @@ language: csharp
 mono: none
 sudo: required
 dist: xenial
-dotnet: 2.2
+dotnet: 3.1
 script:
     - dotnet restore
     - dotnet build AspNetCoreSerilogExample.sln -c Release
 global:
     - DOTNET_SKIP_FIRST_TIME_EXPERIENCE=true
-    - DOTNET_CLI_TELEMETRY_OPTOUT=1
+    - DOTNET_CLI_TELEMETRY_OPTOUT=1