chore: fix travis source flag

Author: twilio-dx

.travis.yml

@@ -13,7 +13,7 @@ deploy:
  skip_cleanup: true
  provider: script
  script: dotnet nuget push /home/travis/build/sendgrid/smtpapi-csharp/*.nupkg --api-key
- $NUGET_API_KEY -Source https://api.nuget.org/v3/index.json
+ $NUGET_API_KEY --source https://api.nuget.org/v3/index.json
  on:
  branch: main
  tags: true