switch to code style and remove --upgrade

README.md

@@ -13,5 +13,6 @@ Requirements:
 * numpy
 
 Install with pip, via git:
-
->pip install --upgrade git+https://mpxd.net/gogs/jan/float_raster.git@release
+```bash
+pip install git+https://mpxd.net/gogs/jan/float_raster.git@release
+```