Update to not require version.py

SConstruct

@@ -5,5 +5,5 @@ scripts.BasicSConstruct(
     "sdm_schemas",
     disableCc=True,
     noCfgFile=True,
-    versionModuleName="python/lsst/sdm/schemas/version.py"
+    versionModuleName=None
 )

pyproject.toml

@@ -35,9 +35,6 @@ dynamic = ["version"]
 [tool.setuptools.dynamic]
 version = { attr = "lsst_versions.get_lsst_version" }
 
-[tool.lsst_versions]
-write_to = "python/lsst/sdm/schemas/version.py"
-
 [project.urls]
 Homepage = "https://sdm-schemas.lsst.io"
 Source = "https://github.com/lsst/sdm_schemas"

python/lsst/sdm/schemas/__init__.py

@@ -0,0 +1,28 @@
+# This file is part of sdm_schemas.
+#
+# Developed for the LSST Data Management System.
+# This product includes software developed by the LSST Project
+# (https://www.lsst.org).
+# See the COPYRIGHT file at the top-level directory of this distribution
+# for details of code ownership.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+from importlib.metadata import PackageNotFoundError, version
+
+try:
+    __version__ = version("lsst-sdm-schemas")
+except PackageNotFoundError:
+    # Package not installed or scons not run.
+    __version__ = "0.0.0"