RasterDataset: fix bug when separate_files and no date in regex (#1191)

torchgeo/datasets/geo.py

@@ -416,7 +416,7 @@ def __getitem__(self, query: BoundingBox) -> Dict[str, Any]:
                     directory = os.path.dirname(filepath)
                     match = re.match(filename_regex, filename)
                     if match:
-                        if "date" in match.groupdict():
+                        if "band" in match.groupdict():
                             start = match.start("band")
                             end = match.end("band")
                             filename = filename[:start] + band + filename[end:]