Include version in HTTP User-Agent header

This allows us to check on the server side whether the user is still using
an up-to-date benchmark client or not.

benchmark/submission/client.py

@@ -33,11 +33,13 @@ class BenchmarkClient:
 
     def __init__(self, mydata_server: str) -> None:
         from requests.adapters import HTTPAdapter
+        from ..version import version
 
         self.auth_token = None
         self.auth_http_server = None
         self.session = requests.Session()
         self.session.mount('https://', HTTPAdapter(max_retries=5))
+        self.session.headers['User-Agent'] = f'blender-benchmark-client/{version}'
 
         self.url_generate_token = urllib.parse.urljoin(mydata_server, 'token/generate')
         self.url_verify_token = urllib.parse.urljoin(mydata_server, 'token/verify')