Add black to dev dependencies and set some defaults

pyproject.toml

@@ -15,6 +15,7 @@ dependencies = [
 
 [project.optional-dependencies]
 dev = [
+    "black",
     "mypy",
     "types-PyYAML",
     "types-Pygments",
@@ -23,6 +24,9 @@ dev = [
 [project.scripts]
 ossg = "omicron.ssg.cli:main"
 
+[tool.black]
+target-version = ["py314"]
+
 [tool.mypy]
 strict = true