[#2144] Install Minio 7.1.16 for Python 3.6.

Minio 7.1.17 uses a Python module that only exists in Python 3.7 and
beyond. This causes the test hook to fail on OS which ship with a
version of Python earlier than 3.7.

Installing the previous version of Minio resolves the issue.

irods_consortium_continuous_integration_test_hook.py

@@ -12,6 +12,7 @@
 import platform
 import distro
 import logging
+import sys
 
 import irods_python_ci_utilities
 
@@ -34,7 +35,13 @@ def get_package_type():
 def install_test_prerequisites():
     irods_python_ci_utilities.subprocess_get_output(['sudo', 'python3', '-m', 'pip', 'install', '--upgrade', 'pip>=20.3.4'], check_rc=True)
     irods_python_ci_utilities.subprocess_get_output(['sudo', 'python3', '-m', 'pip', 'install', 'boto3', '--upgrade'], check_rc=True)
-    irods_python_ci_utilities.subprocess_get_output(['sudo', 'python3', '-m', 'pip', 'install', 'minio', '--upgrade'], check_rc=True)
+
+    # Minio 7.1.17 imports the annontations module which only exists in Python 3.7 and beyond.
+    # For OS which default to Python 3.6, we have to install the previous version of Minio to avoid
+    # compatibility issues. The --upgrade flag is ignored if "minio_version" results in a non-empty string.
+    minio_version = '==7.1.16' if sys.hexversion < 0x030700F0 else ''
+    irods_python_ci_utilities.subprocess_get_output(['sudo', 'python3', '-m', 'pip', 'install', 'minio' + minio_version, '--upgrade'], check_rc=True)
+
     irods_python_ci_utilities.subprocess_get_output(['sudo', '-EH', 'python3', '-m', 'pip', 'install', 'unittest-xml-reporting==1.14.0'])
 
 def download_and_start_minio_server():