Docs: for the dev setup, always update the depenencies

docs/topics/install.rst

@@ -34,7 +34,7 @@ To install additional libraries required by CloudBridge contributors, such as
 `tox <https://tox.readthedocs.org/en/latest/>`_, clone the source code
 repository and run the following command from the repository root directory::
 
-    pip install -e .[dev]
+    pip install -U -e .[dev]
 
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