Update mdb-whats-new.md

Minor title change

Author: chrisda

defender-business/mdb-whats-new.md

@@ -18,7 +18,7 @@ search.appverid: MET150
 audience: Admin
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-# What's new in Microsoft 365 Defender for Business
+# What's new in Microsoft Defender for Business
 
 This article lists new features in the latest releases of Microsoft Defender for Business. Features that are currently in preview are denoted with **(preview)**.