Remove pinned setuptools

pants

@@ -20,16 +20,6 @@ PANTS_BOOTSTRAP="${PANTS_HOME}/bootstrap-$(uname -s)-$(uname -m)"
 
 VENV_VERSION=${VENV_VERSION:-16.0.0}
 
-# This requirement is installed before pantsbuild.pants to hack around
-# interpreters that have newer setuptools already installed, effectively
-# re-installing an older setuptools and pinning low to a version known to be 
-# ingestable by both pants and pex for all reasonable versions of pants.
-# See:
-#   https://github.com/pantsbuild/pants/issues/3948
-#   https://github.com/pantsbuild/setup/issues/14
-#   https://github.com/pantsbuild/setup/issues/19
-SETUPTOOLS_REQUIREMENT="setuptools==5.4.1"
-
 VENV_PACKAGE=virtualenv-${VENV_VERSION}
 VENV_TARBALL=${VENV_PACKAGE}.tar.gz
 
@@ -111,12 +101,9 @@ function bootstrap_pants {
 
   if [[ ! -d "${PANTS_BOOTSTRAP}/${target_folder_name}" ]]; then
     (
-      # NB: We setup the virtualenv with no setuptools to ensure our
-      # ${SETUPTOOLS_REQUIREMENT} wins.
       venv_path="$(bootstrap_venv)"
       staging_dir=$(tempdir "${PANTS_BOOTSTRAP}")
-      "${python}" "${venv_path}/virtualenv.py" --no-setuptools --no-download \
-        "${staging_dir}/install"
+      "${python}" "${venv_path}/virtualenv.py" --no-download "${staging_dir}/install"
       "${staging_dir}/install/bin/pip" install -U pip
       "${staging_dir}/install/bin/pip" install "${SETUPTOOLS_REQUIREMENT}"
       "${staging_dir}/install/bin/pip" install "${pants_requirement}"