Bump github.com/mattermost/mattermost-server in /dependabot (#53)

dependabot/Gopkg.lock

@@ -50,7 +50,7 @@
   version = "v1.10.0"
 
 [[projects]]
-  digest = "1:3fb7fc94193104386c806739d91009069d2629aec857cd9d465fc802310b96fc"
+  digest = "1:49a910602e79923a09c2b6114973078d001caec7fb6803aad25f289f622b353b"
   name = "github.com/mattermost/mattermost-server"
   packages = [
     "mlog",
@@ -60,8 +60,8 @@
     "utils/markdown",
   ]
   pruneopts = ""
-  revision = "dbe330511eb45dcfaca1b5a5fd7e5097d50fc83a"
-  version = "v5.12.1"
+  revision = "b41421c48b634e53921f5e6bfe37878833769df4"
+  version = "v5.12.3"
 
 [[projects]]
   digest = "1:9fa4a4a684dfb36f3ba1b0a163225140e19e3219e5576d0761d02dbd4c31b743"

dependabot/Gopkg.toml

@@ -1,3 +1,3 @@
 [[constraint]]
   name = "github.com/mattermost/mattermost-server"
-  version = "v5.12.1"
+  version = "v5.12.3"