Make build reproducible by reading envvar SOURCE_DATE_EPOCH if set (#…

…3430)

Co-authored-by: Justin Mayer <[email protected]>

docs/conf.py

@@ -1,6 +1,7 @@
 import datetime
 import os
 import sys
+import time
 
 if sys.version_info >= (3, 11):
     import tomllib
@@ -30,7 +31,9 @@
 source_suffix = ".rst"
 master_doc = "index"
 project = project_data.get("name").upper()
-year = datetime.datetime.now().date().year
+year = datetime.datetime.fromtimestamp(
+    int(os.environ.get("SOURCE_DATE_EPOCH", time.time())), datetime.timezone.utc
+).year
 copyright = f"2010–{year}"  # noqa: RUF001
 exclude_patterns = ["_build"]
 release = project_data.get("version")