Add note for ssh users to .lfsconfig

Users using ssh are suddenly asked for a username and password for lfs,
add a note as to why that is and how to avoid it to the .lfsconfig in
hope they will see it.

Signed-off-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>

.lfsconfig

@@ -1,2 +1,8 @@
+# If you are using ssh [1] to push and want to use it to obtain a token instead
+# of using basic auth override this with:
+#     git config lfs.url git@gitea.wildfiregames.com/0ad/0ad.git
+#
+# [1] https://github.com/git-lfs/git-lfs/blob/main/docs/api/server-discovery.md#ssh
+
 [lfs]
 	url = https://gitea.wildfiregames.com/0ad/0ad.git/info/lfs