Fix use of importlib that doesn't work for python 3.6

brian_dashboard_manager/environment.py

 import json
 import logging.config
 import os
-from importlib.metadata import distribution
 import sentry_sdk
 from sentry_sdk.integrations.flask import FlaskIntegration
 
+try:
+    from importlib.metadata import distribution as get_distribution
+except ImportError:
+    from pkg_resources import get_distribution
+
 
 def setup_logging():
     """
@@ -21,7 +25,7 @@ def setup_logging():
         sentry_sdk.init(
             dsn=sentry_dsn,
             integrations=[FlaskIntegration()],
-            release=distribution('brian-dashboard-manager').version)
+            release=get_distribution('brian-dashboard-manager').version)
 
     with open(filename) as f:
         # TODO: this mac workaround should be removed ...

brian_dashboard_manager/routes/version.py

-from importlib.metadata import distribution
+try:
+    from importlib.metadata import distribution as get_distribution
+except ImportError:
+    from pkg_resources import get_distribution
+
 from flask import Blueprint, jsonify
 from brian_dashboard_manager.routes import common
 
@@ -17,6 +21,6 @@ def version():
     version_params = {
         'api': API_VERSION,
         'module':
-            distribution('brian-dashboard-manager').version
+            get_distribution('brian-dashboard-manager').version
     }
     return jsonify(version_params)