The CONTRIBUTING.md requests an (or multiple) SPDX identifier for GPL
licenses. But a lot of packages did use a different, non-SPDX style with a
"+" at the end instead of "-or-later".

Signed-off-by: Sven Eckelmann <sven@narfation.org>

Signed-off-by: Jasper Scholte <NightNL@outlook.com>

Simpler and makes version bumps easier.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

This reintroduces digitemp from the "old unmaintained" repository: http://git.openwrt.org/?p=packages.git;a=tree;f=utils/digitemp;hb=HEAD
Updated to v3.7.1 and based on github as mentioned here: https://www.digitemp.com/software.shtml
Set myself as maintainer.

Signed-off-by: Jasper Scholte <NightNL@outlook.com>