Configured code formatting and update version of pre-commit hooks.

gprMax.toml

@@ -2,3 +2,9 @@
 requires = ['setuptools', 'wheel', 'numpy>=1.19.0', 'Cython>=0.29.21',
             'jinja2']
 build-backend = "setuptools.build_meta"
+
+[tool.black]
+line-length = 120
+
+[tool.isort]
+profile = "black"