remove usage of deprecated Role into Export

src/Bundle/ChillCalendarBundle/Export/Aggregator/AgentAggregator.php

@@ -33,7 +33,7 @@ final class AgentAggregator implements AggregatorInterface
         $this->userRender = $userRender;
     }
 
-    public function addRole()
+    public function addRole(): ?string
     {
         return null;
     }

src/Bundle/ChillCalendarBundle/Export/Aggregator/CancelReasonAggregator.php

@@ -33,7 +33,7 @@ class CancelReasonAggregator implements AggregatorInterface
         $this->translatableStringHelper = $translatableStringHelper;
     }
 
-    public function addRole()
+    public function addRole(): ?string
     {
         return null;
     }

src/Bundle/ChillCalendarBundle/Export/Aggregator/JobAggregator.php

@@ -33,7 +33,7 @@ final class JobAggregator implements AggregatorInterface
         $this->translatableStringHelper = $translatableStringHelper;
     }
 
-    public function addRole()
+    public function addRole(): ?string
     {
         return null;
     }

src/Bundle/ChillCalendarBundle/Export/Aggregator/LocationAggregator.php

@@ -29,7 +29,7 @@ final class LocationAggregator implements AggregatorInterface
         $this->locationRepository = $locationRepository;
     }
 
-    public function addRole(): ?Role
+    public function addRole(): ?string
     {
         return null;
     }

src/Bundle/ChillCalendarBundle/Export/Aggregator/LocationTypeAggregator.php

@@ -33,7 +33,7 @@ final class LocationTypeAggregator implements AggregatorInterface
         $this->translatableStringHelper = $translatableStringHelper;
     }
 
-    public function addRole()
+    public function addRole(): ?string
     {
         return null;
     }

src/Bundle/ChillCalendarBundle/Export/Aggregator/MonthYearAggregator.php

@@ -20,7 +20,7 @@ use Symfony\Component\Security\Core\Role\Role;
 
 class MonthYearAggregator implements AggregatorInterface
 {
-    public function addRole(): ?Role
+    public function addRole(): ?string
     {
         return null;
     }

src/Bundle/ChillCalendarBundle/Export/Aggregator/ScopeAggregator.php

@@ -33,7 +33,7 @@ final class ScopeAggregator implements AggregatorInterface
         $this->translatableStringHelper = $translatableStringHelper;
     }
 
-    public function addRole()
+    public function addRole(): ?string
     {
         return null;
     }