Although the use of LastModified dates for caching of git objects should be
discouraged (as it is not native to git - and there are a LOT of ways this
could be incorrect) - LastModified dates can be a helpful somewhat more human
way of caching for simple cases.
This PR adds this header and handles the If-Modified-Since header to the /raw/
routes.
Fix #18354
Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: 6543 <6543@obermui.de>
9f5ddca57c