docs(migrate10): add entry for "portGeneration"

docs/guides/migration/migrate10.md

@@ -6,7 +6,7 @@ title: 'Migrate to version 10.0.0'
 Here are the Important changes made for 10.0.0
 
 :::caution Important, Read this first
-This Guide is written for migration from version `9.4.0` to `10.0.0`, for versions `>10.0.0 <11.0.0`, please consult the [CHANGELOG](https://github.com/typegoose/mongodb-memory-server/blob/master/CHANGELOG.md)
+This Guide is written for migration from version `9.4.1` to `10.0.0`, for versions `>10.0.0 <11.0.0`, please consult the [CHANGELOG](https://github.com/typegoose/mongodb-memory-server/blob/master/CHANGELOG.md)
 :::
 
 ## Breaking Changes
@@ -40,3 +40,9 @@ This should be a non-breaking change.
 
 This means a port is now generated by the engine (like nodejs) itself, previously known as `EXP_NET0LISTEN`.
 This should reduce amount of `Max port tries exceeded` errors.
+
+### Allow setting port generation in MongoMemoryServer
+
+Starting with 10.0 there is a new option to set whether port generation is enabled or not on `MongoMemoryServer` called `portGeneration`. (default: `true`)
+
+(Note that the `forceSamePort` parameter in `.start` will overwrite this option)