use setuptools-scm style version

setup.py

@@ -7,24 +7,41 @@ class VrsSubmoduleFetchError(Exception):
     """Raise for errors during submodule metadata extraction"""
 
 
-def get_vrs_submodule_info():
-    """Retrieve the commit hash and tag from the vrs submodule."""
+def _get_vrs_submodule_info() -> tuple[str, str, int]:
+    """Retrieve the commit hash and tag from the vrs submodule.
+
+    :return: tuple containing commit hash, latest version tag, and rev distance between them
+    """
     try:
-        return subprocess.check_output(
-            ["git", "describe", "--tags", "--abbrev=0"], cwd="submodules/vrs", text=True
+        vrs_path = "submodules/vrs"
+        commit = subprocess.check_output(
+            ["git", "rev-parse", "HEAD"], cwd=vrs_path, text=True
+        ).strip()
+        tag = subprocess.check_output(
+            ["git", "describe", "--tags", "--abbrev=0"], cwd=vrs_path, text=True
+        ).strip()
+        distance =  subprocess.check_output(
+            ["git", "rev-list", f"{tag}..HEAD", "--count"],
+            cwd=vrs_path,
+            text=True,
         ).strip()
+        return commit, tag, int(distance)
     except Exception as e:
         raise VrsSubmoduleFetchError from e
 
 
 def write_metadata_file():
     """Generate a Python module with submodule metadata."""
-    tag = get_vrs_submodule_info()
+    commit, tag, distance = _get_vrs_submodule_info()
     metadata_path = Path("src/ga4gh/vrs/submodule_metadata.py")
     metadata_path.parent.mkdir(parents=True, exist_ok=True)
+    if distance == 0:
+        version = tag
+    else:
+        version = f"{tag}.dev{distance}+g{commit}"
     metadata_path.write_text(
         f"# Auto-generated metadata from VRS schema submodule\n"
-        f"VRS_RELEASE = '{tag}'\n"
+        f"VRS_VERSION = '{version}'\n"
     )
 
 

src/ga4gh/vrs/submodule_metadata.py

@@ -1,2 +1,2 @@
-# Auto-generated metadata for VRS submodule
-VRS_TAG = '2.0.0.connect.2024-04.1'
+# Auto-generated metadata from VRS schema submodule
+VRS_VERSION = '2.0.0.connect.2024-04.1.dev83+gcf968d24a37cefca5a2f363f0e2f36741cd12ad5'