lowercase email during import and expert update

src/main/java/fr/gouv/beta/selexpert/dto/ImportFileHeaderAppealCourt.java

@@ -31,7 +31,10 @@ public enum ImportFileHeaderAppealCourt implements ImportFileHeader {
   VILLE("ville", null),
   CODE_POSTAL("code_postal", null),
   DEPARTEMENT("departement", null),
-  COURRIEL("courriel", null),
+  COURRIEL(
+      "courriel",
+      (String content) ->
+          content.matches("(^$|[a-zA-Z0-9._%+\\-']+@[a-zA-Z0-9.\\-àèéÀÈÉ]+\\.[a-zA-Z]{2,12})")),
   FAX("fax", null),
   MOBILE("mobile", null),
   FIXE("fixe", null),