build: Add .version to EXTRA_DIST
build: Add .version to EXTRA_DIST

This fixes make distcheck and this is equivalent to what we did
in libosmocore commit e28bc6876d127e1165dc7ad2ea96b585a1161ec6

Signed-off-by: Sylvain Munaut <349f318521b45672c77207abf1a5ed60eb011db1@246tNt.com>

marcelmaatkamp/gnuradio-osmocom-gmr,marcelmaatkamp/docker-gnuradio-osmocom-gmr,marcelmaatkamp/docker-gnuradio-osmocom-gmr,marcelmaatkamp/gnuradio-osmocom-gmr,marcelmaatkamp/docker-gnuradio-osmocom-gmr,marcelmaatkamp/gnuradio-osmocom-gmr