docs: add example of the field version (#5609)

Author: ldez

docs/src/docs/product/migration-guide.mdx

@@ -2007,6 +2007,10 @@ severity:
 
 The `version` property has been added to the configuration file.
 
+```yaml
+version: "2"
+```
+
 ### Integration
 
 #### VSCode

docs/src/docs/usage/configuration.mdx

@@ -42,6 +42,14 @@ The configuration file can be validated with the JSON Schema: https://golangci-l
 
 { .ConfigurationExample }
 
+### Configuration Version
+
+```yaml
+# Defines the configuration version.
+# The only possible value is "2".
+version: "2"
+```
+
 ## Command-Line Options
 
 ### run