fix: removed some validations for 'completionDate'

They not always work correctly.

Author: Maksym Mykhailenko

src/routes/milestones/bulkUpdate.js

@@ -25,8 +25,8 @@ const schema = {
     duration: Joi.number().integer().min(1).optional(),
     startDate: Joi.date().required(),
     actualStartDate: Joi.date().allow(null),
-    endDate: Joi.date().min(Joi.ref('startDate')).allow(null),
-    completionDate: Joi.date().min(Joi.ref('startDate')).allow(null),
+    endDate: Joi.date().allow(null),
+    completionDate: Joi.date().allow(null),
     status: Joi.string().max(45).optional(),
     type: Joi.string().max(45).optional(),
     details: Joi.object(),

src/routes/milestones/create.js

@@ -24,7 +24,7 @@ const schema = {
     startDate: Joi.date().required(),
     actualStartDate: Joi.date().allow(null),
     endDate: Joi.date().min(Joi.ref('startDate')).allow(null),
-    completionDate: Joi.date().min(Joi.ref('startDate')).allow(null),
+    completionDate: Joi.date().allow(null),
     status: Joi.string().max(45).required(),
     type: Joi.string().max(45).required(),
     details: Joi.object(),