Readding lager

Due to an incompatibilitiy with versions of lager > 3.6.8, Antidote won't compile on Erlang 21 on MacOS X. By adding lager back as a top-level dependency and running `rebar3 upgrade lager`, we enforce the most recent version.

rebar.config

@@ -12,6 +12,7 @@
     {antidote_pb_codec, "0.0.5"},
     {antidotec_pb, "0.2.4"},
     {vectorclock, "0.1.0"},
+    lager,
 
     % expose metrics for prometheus as HTTP-API
     {elli, "2.1.2"},

rebar.lock

@@ -21,7 +21,7 @@
  {<<"gen_fsm_compat">>,{pkg,<<"gen_fsm_compat">>,<<"0.3.0">>},1},
  {<<"getopt">>,{pkg,<<"getopt">>,<<"1.0.1">>},2},
  {<<"goldrush">>,{pkg,<<"goldrush">>,<<"0.1.9">>},1},
- {<<"lager">>,{pkg,<<"lager">>,<<"3.6.2">>},1},
+ {<<"lager">>,{pkg,<<"lager">>,<<"3.6.8">>},0},
  {<<"parse_trans">>,{pkg,<<"parse_trans">>,<<"3.3.0">>},2},
  {<<"pbkdf2">>,{pkg,<<"pbkdf2">>,<<"2.0.0">>},1},
  {<<"poolboy">>,{pkg,<<"basho_poolboy">>,<<"0.8.4">>},1},
@@ -56,7 +56,7 @@
  {<<"gen_fsm_compat">>, <<"5903549F67D595F58A7101154CBE0FDD46955FBFBE40813F1E53C23A970FF5F4">>},
  {<<"getopt">>, <<"C73A9FA687B217F2FF79F68A3B637711BB1936E712B521D8CE466B29CBF7808A">>},
  {<<"goldrush">>, <<"F06E5D5F1277DA5C413E84D5A2924174182FB108DABB39D5EC548B27424CD106">>},
- {<<"lager">>, <<"2C72950A0E75FFD927DD35BC85EA30E7680A264C4BBD08B328250871AC456CC2">>},
+ {<<"lager">>, <<"897EFC7679BB82383448646C96768CDC4E747464DD18B999C7AACA485686B0DA">>},
  {<<"parse_trans">>, <<"09765507A3C7590A784615CFD421D101AEC25098D50B89D7AA1D66646BC571C1">>},
  {<<"pbkdf2">>, <<"11C23279FDED5C0027AB3996CFAE77805521D7EF4BABDE2BD7EC04A9086CF499">>},
  {<<"poolboy">>, <<"45C306FF1C9F6451730DD21642EDF55FA72EBD5E2FE4A38D8D8A56B8EA21A256">>},