Use pixi-build-cmake version range for broad pixi compatibility

Instead of pinning ==0.3.8 (which requires pixi >=0.63), use the range
>=0.3.6,<=0.3.8 so pixi automatically selects the correct backend API
version for the user's installed pixi. This matches the approach used
in molecularGSM and avoids forcing all collaborators to upgrade pixi
simultaneously.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: joshkamm

pixi.lock

@@ -2,17 +2,15 @@
 channels = ["nvidia", "conda-forge"]
 platforms = ["linux-64", "linux-aarch64"]
 preview = ["pixi-build"]
-# Minimum pixi version: 0.63.0 required for pixi-build-cmake 0.3.8 (build API v4)
-requires-pixi = ">=0.63"
+requires-pixi = ">=0.60.0"
 
 [package]
 name = "slatergpu"
 version = "0.1.14"
 
 [package.build.backend]
 name = "pixi-build-cmake"
-# NOTE: pixi-build-cmake 0.3.5+ requires build API v4, which means pixi >= 0.63.0
-version = "==0.3.8"
+version = ">=0.3.6,<=0.3.8"
 
 [package.build.config]
 compilers = []