build: add build_scripts/env.py to the hashed files

It contains information that define the build environments, and as such, modifying it should result in a new release of the dev containers.

dev_scripts/env.py

@@ -292,6 +292,7 @@ def get_build_dir_sources(distro, version):
     sources = [
         git_root() / "pyproject.toml",
         git_root() / "poetry.lock",
+        git_root() / "dev_scripts" / "env.py",
         git_root() / "dev_scripts" / "storage.conf",
         git_root() / "dev_scripts" / "containers.conf",
     ]