Add simple_enum.avro and simple_fixed.avro

Author: sarutak

data/avro/README.md

@@ -41,4 +41,6 @@ Additional notes:
 | File  | Description   |
 |:--|:--|
 | alltypes_nulls_plain.avro   | Contains a single row with null values for each scalar data type, i.e, `{"string_col":null,"int_col":null,"bool_col":null,"bigint_col":null,"float_col":null,"double_col":null,"bytes_col":null}`. Generated from https://gist.github.com/nenorbot/5a92e24f8f3615488f75e2a18a105c76   |
-| nested_records.avro | Contains two rows of nested record types. Generated from https://github.com/sarutak/avro-data-generator/blob/master/src/bin/nested-records.rs |
+| nested_records.avro | Contains two rows of nested record types. Generated from https://github.com/sarutak/avro-data-generator/blob/master/src/bin/nested-records.rs |
+| simple_enum.avro | Contains four rows of enum types. Generated from https://github.com/sarutak/avro-data-generator/blob/master/src/bin/simple-enum.rs |
+| simple_fixed | Contains two rows of fixed types. Generated from https://github.com/sarutak/avro-data-generator/blob/master/src/bin/simple-fixed.rs |