fix DOTNET version number (#3347)

12.22.0 was supposed to be 12.2.0

## Pull Request Info
Jira ticket: DOCSP-41878

*Staged Page*

- [Define an Object
Model](https://preview-mongodbmongocaleb.gatsbyjs.io/realm/DOCSP-41878/sdk/dotnet/model-data/define-object-model/)
- [Value
Type](https://preview-mongodbmongocaleb.gatsbyjs.io/realm/DOCSP-41878/sdk/dotnet/model-data/data-types/realm-value/)

source/sdk/dotnet/model-data/data-types/realm-value.txt

@@ -42,7 +42,7 @@ that property:
 Collections as Mixed
 --------------------
 
-In version 12.22.0 and later, a ``RealmValue`` data type can hold collections
+In version 12.2.0 and later, a ``RealmValue`` data type can hold collections
 (a list or dictionary, but *not* a set) of ``RealmValue`` elements. You can use
 mixed collections to model unstructured or variable data. For more information,
 refer to :ref:`<dotnet-model-unstructured-data>`.

source/sdk/dotnet/model-data/define-object-model.txt

@@ -264,9 +264,10 @@ but the public ``Email`` property, which provides validation, is not persisted:
 Define Unstructured Data
 -----------------------
 
-.. versionadded:: 12.22.0
+.. versionadded:: 12.2.0
 
-Starting in SDK version 12.22.0, you can store :ref:`collections of mixed data <dotnet-nested-collections-realm-value>`
+Starting in SDK version 12.2.0, you can store 
+:ref:`collections of mixed data <dotnet-nested-collections-realm-value>`
 within a ``RealmValue`` property. You can use this feature to model complex data
 structures, such as JSON or MongoDB documents, without having to define a
 strict data model.