Silence the pip version warnings

cibuildwheel/linux.py

@@ -94,6 +94,7 @@ def build(options: BuildOptions) -> None:
 
                     env = docker.get_environment()
                     env['PATH'] = f'/opt/python/cp38-cp38/bin:{env["PATH"]}'
+                    env['PIP_DISABLE_PIP_VERSION_CHECK'] = '1'
                     env = options.environment.as_dictionary(env, executor=docker.environment_executor)
 
                     before_all_prepared = prepare_command(options.before_all, project=container_project_path, package=container_package_dir)

cibuildwheel/macos.py

@@ -195,6 +195,9 @@ def setup_python(python_configuration: PythonConfiguration,
     env.pop('__PYVENV_LAUNCHER__', None)
     env = environment.as_dictionary(prev_environment=env)
 
+    # we version pip ourselves, so we don't care about pip version checking
+    env['PIP_DISABLE_PIP_VERSION_CHECK'] = '1'
+
     # check what version we're on
     call(['which', 'python'], env=env)
     call(['python', '--version'], env=env)

cibuildwheel/windows.py

@@ -143,6 +143,8 @@ def setup_python(python_configuration: PythonConfiguration, dependency_constrain
         str(installation_path / 'Scripts'),
         env['PATH']
     ])
+    env['PIP_DISABLE_PIP_VERSION_CHECK'] = '1'
+
     # update env with results from CIBW_ENVIRONMENT
     env = environment.as_dictionary(prev_environment=env)