chore(deps): update dependency futures to v3.4.0 (googleapis#850)

* chore(deps): update dependency futures to v3.4.0

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

samples/samples/noxfile.py

@@ -180,7 +180,6 @@ def blacken(session: nox.sessions.Session) -> None:
 # format = isort + black
 #
 
-
 @nox.session
 def format(session: nox.sessions.Session) -> None:
     """
@@ -208,9 +207,7 @@ def _session_tests(
     session: nox.sessions.Session, post_install: Callable = None
 ) -> None:
     # check for presence of tests
-    test_list = glob.glob("**/*_test.py", recursive=True) + glob.glob(
-        "**/test_*.py", recursive=True
-    )
+    test_list = glob.glob("**/*_test.py", recursive=True) + glob.glob("**/test_*.py", recursive=True)
     test_list.extend(glob.glob("**/tests", recursive=True))
 
     if len(test_list) == 0:
@@ -232,7 +229,9 @@ def _session_tests(
 
     if os.path.exists("requirements-test.txt"):
         if os.path.exists("constraints-test.txt"):
-            session.install("-r", "requirements-test.txt", "-c", "constraints-test.txt")
+            session.install(
+                "-r", "requirements-test.txt", "-c", "constraints-test.txt"
+            )
         else:
             session.install("-r", "requirements-test.txt")
         with open("requirements-test.txt") as rtfile:
@@ -245,9 +244,9 @@ def _session_tests(
         post_install(session)
 
     if "pytest-parallel" in packages:
-        concurrent_args.extend(["--workers", "auto", "--tests-per-worker", "auto"])
+        concurrent_args.extend(['--workers', 'auto', '--tests-per-worker', 'auto'])
     elif "pytest-xdist" in packages:
-        concurrent_args.extend(["-n", "auto"])
+        concurrent_args.extend(['-n', 'auto'])
 
     session.run(
         "pytest",
@@ -277,7 +276,7 @@ def py(session: nox.sessions.Session) -> None:
 
 
 def _get_repo_root() -> Optional[str]:
-    """Returns the root folder of the project."""
+    """ Returns the root folder of the project. """
     # Get root of this repository. Assume we don't have directories nested deeper than 10 items.
     p = Path(os.getcwd())
     for i in range(10):

samples/samples/requirements.txt

@@ -1,2 +1,2 @@
 google-cloud-spanner==3.22.2
-futures==3.3.0; python_version < "3"
+futures==3.4.0; python_version < "3"