upgrade to lager 3.9.1 (fix builds with Erlang/OTP 24)

Change-Id: I704855533caf00046aa046d2ac9358adeadbca31
---
M rebar.config
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rebar.config b/rebar.config
index 86444dd..0803ccd 100644
--- a/rebar.config
+++ b/rebar.config
@@ -2,7 +2,7 @@
 
 {deps, [
 	{setup, "2.0.2"},
-	{lager, "3.6.8"},
+	{lager, {git, "https://github.com/erlang-lager/lager", {tag, "3.9.1"}}},
 	{osmo_ss7, {git, "git://git.osmocom.org/erlang/osmo_ss7", {branch, "laforge/wip"}}},
 	{osmo_gsup,  {git, "git://git.osmocom.org/erlang/osmo_gsup", {branch, "master"}}}
 ]}.

