Document codespaces

Author: robmarkcole

README.md

@@ -49,5 +49,8 @@ docker build --tag iris .
 docker run -p 80:80 -v <dataset_path>:/dataset/ --rm -it iris label /dataset/cloud-segmentation.json
 ```
 
+### Run on Github Codespaces
+To run in a [Github codespace](https://docs.github.com/en/codespaces/overview) fork this repository, then in the Github UI select `Code/Codespaces/Open in codespace`. Run `pip install -e .` and then `iris demo`. You will see a popup that there is an app on port 5000, click the link to open a new window showing Iris 🎉
+
 
 **Visit the official iris Github page:  https://github.com/ESA-PhiLab/iris**

requirements.txt

@@ -2,7 +2,7 @@ flask==2.3.2
 flask_compress==1.13
 flask-sqlalchemy==2.5.1
 numpy==1.23.4
-pyyaml==5.4.1
+pyyaml>=5.4.1
 lightgbm==3.3.3
 rasterio==1.3.3
 requests==2.28.1