Updated docs to use pip show

Show the current DRF version using `pip show`

Closes #5757

Author: LuD1161

docs/topics/release-notes.md

@@ -32,9 +32,9 @@ To upgrade Django REST framework to the latest version, use pip:
 
     pip install -U djangorestframework
 
-You can determine your currently installed version using `pip freeze`:
+You can determine your currently installed version using `pip show`:
 
-    pip freeze | grep djangorestframework
+    pip show djangorestframework
 
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