fix: pip3 install now does not accept the --use-feature=in-tree-build (#146)

The feature flag `--use-feature=in-tree-build` was introduced in pip 21.1 and then
the feature was mainlined in pip 21.3.  With the flag in place `pip install` command
fails and `kic_utils` fails to build.

Based on the changelog which states that this behavior is default in pip 21.3+ and the current
build installs pip 22.1 we remove the flag.

fixes #145

Author: 4141done

bin/setup_venv.sh

@@ -197,7 +197,7 @@ fi
 # Install general package requirements
 pip3 install --requirement "${script_dir}/../pulumi/python/requirements.txt"
 # Install local common utilities module
-pip3 install --use-feature=in-tree-build "${script_dir}/../pulumi/python/utility/kic-pulumi-utils" &&
+pip3 install "${script_dir}/../pulumi/python/utility/kic-pulumi-utils" &&
   rm -rf "${script_dir}/../pulumi/python/utility/kic-pulumi-utils/.eggs" \
     "${script_dir}/../pulumi/python/utility/kic-pulumi-utils/build" \
     "${script_dir}/../pulumi/python/utility/kic-pulumi-utils/kic_pulumi_utils.egg-info"