dfn: add netcdf to v2 field (#265)

Author: mjreno

modflow_devtools/dfn/schema/field.py

@@ -18,3 +18,4 @@ class Field:
     developmode: bool = False
     shape: str | None = None
     valid: tuple[str, ...] | None = None
+    netcdf: bool = False

modflow_devtools/dfn/schema/v1.py

@@ -36,7 +36,7 @@ class FieldV1(Field):
     deprecated: bool = False
     removed: bool = False
     mf6internal: str | None = None
-    netcdf: str | None = None
+    netcdf: bool = False
     block_variable: bool = False
     just_data: bool = False