feat: updates python and dependency versions (#1826)

Updates the Python versions and versions of several of the primary tools listed in the install commands.

noxfile.py

@@ -14,29 +14,34 @@
 
 import nox
 
-@nox.session(python=['3.6', '3.10'])
+PYTHON_VERSIONS = ['3.8', '3.10']
+
+# Error if a python version is missing
+nox.options.error_on_missing_interpreters = True
+
+@nox.session(python=PYTHON_VERSIONS)
 def generate_protos(session):
     session.install("grpcio-tools")
     session.run(
         "python", "-m", "grpc_tools.protoc", "-Isynthtool/protos", "--python_out=synthtool/protos", "synthtool/protos/metadata.proto", "synthtool/protos/preconfig.proto")
 
-@nox.session(python=['3.6', '3.10'])
+@nox.session(python=PYTHON_VERSIONS)
 def blacken(session):
-    session.install('black==22.3.0', 'click>8.0')
+    session.install('black==23.3.0', 'click>8.0')
     session.run('black', 'synthtool', 'tests')
 
 
-@nox.session(python=['3.6', '3.10'])
+@nox.session(python=PYTHON_VERSIONS)
 def lint(session):
-    session.install('mypy==0.790', 'flake8', 'black==22.3.0')
+    session.install('mypy==0.790', 'flake8', 'black==23.3.0')
     session.run('pip', 'install', '-e', '.')
     session.run('pip', 'install', 'click>8.0')
     session.run('black', '--check', 'synthtool', 'tests')
     session.run('flake8', 'synthtool', 'tests')
     session.run('mypy', 'synthtool')
 
 
-@nox.session(python=['3.6', '3.10'])
+@nox.session(python=PYTHON_VERSIONS)
 def test(session):
     session.install('pytest', 'pytest-cov', 'requests_mock', 'watchdog', 'flake8')
     session.run('pip', 'install', '-e', '.')

tests/test_language_java.py

@@ -98,7 +98,7 @@ def assert_valid_yaml(file):
 
         # lint xml, yaml files
         # use os.walk because glob ignores hidden directories
-        for (dirpath, _, filenames) in os.walk(workdir):
+        for dirpath, _, filenames in os.walk(workdir):
             for file in filenames:
                 (_, ext) = os.path.splitext(file)
                 if ext == ".xml":