Update README.md

Redistributed from https://drive.google.com/file/d/1DnPSU5nVSN7xv95bpZ3XQ0JhKXZOKgIv without modification. Only converted the RAR file to a ZIP file. Please cite https://doi.org/10.1109/jproc.2017.2675998 if you use this dataset.

README.md

@@ -1,3 +1,8 @@
----
-license: unknown
----
+---
+license: unknown
+task_categories:
+- image-classification
+pretty_name: NWPU RESISC45
+size_categories:
+- 10K<n<100K
+---