Begin development on version 5.0.0

Change-Id: I2a3dde690d3cc2c66fb894540870b6ac1f2bbad5

Author: samtstern

buildSrc/src/main/kotlin/Config.kt

@@ -1,5 +1,5 @@
 object Config {
-    const val version = "4.4.0-SNAPSHOT"
+    const val version = "5.0.0-SNAPSHOT"
     val submodules = listOf("auth", "auth-github", "common", "firestore", "database", "storage")
 
     private const val kotlinVersion = "1.2.61"