Use pip to install from sources

The `setup.py install` command is deprecated since setuptools 58.3.0:
https://setuptools.pypa.io/en/latest/history.html#v58-3-0.

Change-Id: I29771a23d3040593d68d5548e326985f0bb176a3
Signed-off-by: François Magimel <magimel.francois@gmail.com>

Author: Linkid

doc/source/admin/install/install-source.rst

@@ -1,14 +1,21 @@
 Install from source
 ===================
 
+.. note::
+
+   In the commands below, substitute "<release>" for your version of choice,
+   such as "queens" or "rocky".
+
+   If you use the development version, replace "stable/<release>" with "master".
+
 Install the services
 --------------------
 
 Retrieve and install cloudkitty::
 
     git clone https://opendev.org/openstack/cloudkitty.git
     cd cloudkitty
-    python setup.py install
+    pip install -c https://opendev.org/openstack/requirements/raw/branch/stable/<release>/upper-constraints.txt .
 
 This procedure installs the ``cloudkitty`` python library and the
 following executables:
@@ -37,7 +44,7 @@ Retrieve and install cloudkitty client::
 
     git clone https://opendev.org/openstack/python-cloudkittyclient.git
     cd python-cloudkittyclient
-    python setup.py install
+    pip install -c https://opendev.org/openstack/requirements/raw/branch/stable/<release>/upper-constraints.txt .
 
 Install the dashboard module
 ----------------------------
@@ -46,7 +53,7 @@ Install the dashboard module
 
     git clone https://opendev.org/openstack/cloudkitty-dashboard.git
     cd cloudkitty-dashboard
-    python setup.py install
+    pip install -c https://opendev.org/openstack/requirements/raw/branch/stable/<release>/upper-constraints.txt .
 
 #. Find where the python packages are installed::