Add "gliner" tag

Hello!

## Pull Request overview
- Add a "gliner" tag

## Details
This should add a "Use in GLiNER" button in the top right of the model. This makes it a bit easier for people to figure out how to actually run this model.

- Tom Aarsen

README.md

@@ -2,6 +2,8 @@
 license: apache-2.0
 datasets:
 - EmergentMethods/AskNews-NER-v0
+tags:
+- gliner
 ---
 # Model Card for gliner_medium_news-v2.1