Added Logs to Unity.gitignore, which is automatically generated in Unity 2018.3 to log package updates.

Unity.gitignore

@@ -3,6 +3,7 @@
 [Oo]bj/
 [Bb]uild/
 [Bb]uilds/
+[Ll]ogs/
 Assets/AssetStoreTools*
 
 # Visual Studio cache directory