Updating to Unity 2019.2.12f1.

ProjectSettings/ProjectVersion.txt

-m_EditorVersion: 2019.2.11f1
-m_EditorVersionWithRevision: 2019.2.11f1 (5f859a4cfee5)
+m_EditorVersion: 2019.2.12f1
+m_EditorVersionWithRevision: 2019.2.12f1 (b1a7e1fb4fa5)