make maturin optional

docs/index.md

@@ -78,17 +78,17 @@ There are many valid ways one could compress this tree. If we add the restrictio
 q.compress()
 ````
 
+```{warning}
 Without the above restriction we could, for example, have:
 
-```
+    root
-root
+    ├── class=od, expver=0001/0002, param=1/2
-├── class=od, expver=0001/0002, param=1/2
+    └── class=rd
-└── class=rd
         ├── expver=0001, param=3
         └── expver=0001/0002, param=1/2
-```
 
 but we do not allow this because it would mean we would have to take multiple branches in order to find data with `expver=0001`.
+```
 
 What we have now is a tree of dense datacubes which represents a single larger sparse datacube in a more compact manner. For want of a better word we'll call it a Qube.
 

pyproject.toml

@@ -1,6 +1,6 @@
 [build-system]
-requires = ["maturin>=1.7,<2.0"]
+requires = ["setuptools", "wheel"]
-build-backend = "maturin"
+build-backend = "setuptools.build_meta"
 
 [project]
 name = "qubed"
@@ -27,7 +27,7 @@ features = ["pyo3/extension-module"]
 
 
 [project.optional-dependencies]
-rust-backend = ["maturin", "pyo3"]
+rust-backend = ["maturin>=1.7,<2.0", "pyo3"]
 
 stac_server = [
     "fastapi",