update go-md2man to v1.0.6

Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>

man/glide.lock

@@ -4,7 +4,7 @@ imports:
 - name: github.com/BurntSushi/toml
   version: f0aeabca5a127c4078abb8c8d64298b147264b55
 - name: github.com/cpuguy83/go-md2man
-  version: 2724a9c9051aa62e9cca11304e7dd518e9e41599
+  version: a65d4d2de4d5f7c74868dfa9b202a3c8be315aaa
   subpackages:
   - md2man
 - name: github.com/fsnotify/fsnotify