docs: update CRD path for multi-group api

Added missing documentation for updating CRD paths update for envtest.

Signed-off-by: Abdul Halim <[email protected]>

Author: ahalimx86

docs/book/src/migration/multi-group.md

@@ -77,6 +77,15 @@ Also, note that the controllers will be created under `controllers/<group>` inst
 That is the reason why we moved the previously generated APIs with the provided scripts in the previous steps. 
 Remember to update the references afterwards.
 
+For envtest to install CRDs correctly into the test environment, the relative path to the CRD directory needs to be updated accordingly in each `controllers/<group>/suite_test.go` file. We need to add additional `".."` to our CRD directory relative path as shown below.
+
+```go
+    By("bootstrapping test environment")
+    testEnv = &envtest.Environment{
+        CRDDirectoryPaths: []string{filepath.Join("..", "..", "config", "crd", "bases")},
+    }
+```
+
 The [CronJob tutorial][cronjob-tutorial] explains each of these changes in
 more detail (in the context of how they're generated by KubeBuilder for
 single-group projects).