clang-format: add AfterCaseLabel option from clang-10

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Id230561133d147c223cee3fb033978373b72f6c6
diff --git a/style/cpp/.clang-format b/style/cpp/.clang-format
index 11f72b2..ef6f54e 100644
--- a/style/cpp/.clang-format
+++ b/style/cpp/.clang-format
@@ -20,6 +20,7 @@
 BinPackArguments: true
 BinPackParameters: true
 BraceWrapping:
+  AfterCaseLabel:  true
   AfterClass:      true
   AfterControlStatement: true
   AfterEnum:       true