REF: Setup.cfg updates (#3)

Author: snowman2

setup.cfg

@@ -6,7 +6,7 @@ description = Toolkit to generate Global Area Reference System grids.
 keywords = GARS, grid
 long_description = file: README.rst
 license = BSD License
-license-file = LICENSE
+license_file = LICENSE
 platform = any
 classifiers =
     Development Status :: 2 - Pre-Alpha
@@ -37,6 +37,9 @@ install_requires =
     pyproj>=3.0.0
 tests_require = pytest-cov
 
+[options.packages.find]
+include = gars_field*
+
 [options.extras_require]
 dev =
     pytest-cov