Remove trailing colon from headers

Author: morozov

UPGRADE.md

@@ -17,7 +17,7 @@ The `version` column platform option is no longer supported.
 The `jsonb` column platform option is no longer supported. `JSONB` columns on PostgreSQL are now introspected
 as columns of type `JSONB`, not as columns of type `JSON` with `jsonb` option set.
 
-## BC BREAK: Classes marked as read-only:
+## BC BREAK: Classes marked as read-only
 
 The following classes have been marked as read-only:
 
@@ -60,7 +60,7 @@ The following classes have been marked as read-only:
 - `Doctrine\DBAL\Tools\Console\ConnectionProvider\SingleConnectionProvider`
 - `Doctrine\DBAL\Tools\DsnParser`
 
-## BC BREAK: Classes marked as final:
+## BC BREAK: Classes marked as final
 
 The following classes have been marked as final: