Fix --silent errors for ibrarian-puppet

Following an upgrade to git 2.14.1 I was getting the following error:

```
[Librarian] Git: /usr/bin/git
error: unknown option `silent'
usage: git version [<options>]

    --build-options       also print build options
```

Digging into this I found voxpupuli/librarian-puppet#52 which shows a
fix by including the latest `librarianp` gem. This fixes the issue for
me however more digging into the architecture of `librarian-puppet` will
be required to understand this issue better.

Gemfile

@@ -2,8 +2,11 @@ source "https://rubygems.org"
 
 gem "boxen",                  "~> 2.9.0"
 gem "hiera",                  "~> 1.3.3"
-gem "librarian-puppet",       "~> 1.0.9"
+gem "librarian-puppet"
 gem "puppet",                 "3.7.1"
+gem "librarianp",
+  git: "https://github.com/voxpupuli/librarian.git",
+  branch: "librarianp"
 gem "puppet-lint",            "0.3.2"
 gem "puppetlabs_spec_helper", "0.4.1"
 gem "open4",                  "~> 1.3.4"

Gemfile.lock

@@ -1,3 +1,11 @@
+GIT
+  remote: https://github.com/voxpupuli/librarian.git
+  revision: 4d78d88be2d7673a136e78760085fbf9664ff27d
+  branch: librarianp
+  specs:
+    librarianp (0.6.3)
+      thor (~> 0.15)
+
 GEM
   remote: https://rubygems.org/
   specs:
@@ -28,7 +36,7 @@ GEM
     highline (1.6.21)
     jmespath (1.0.2)
       multi_json (~> 1.0)
-    json (1.8.3)
+    json (2.1.0)
     json_pure (1.8.2)
     librarian (0.1.2)
       highline
@@ -91,7 +99,7 @@ GEM
       net-ssh (>= 2.7, < 4.0)
       net-telnet
       sfl
-    thor (0.19.1)
+    thor (0.20.0)
 
 PLATFORMS
   ruby
@@ -101,7 +109,8 @@ DEPENDENCIES
   boxen (~> 2.9.0)
   deep_merge (~> 1.0)
   hiera (~> 1.3.3)
-  librarian-puppet (~> 1.0.9)
+  librarian-puppet
+  librarianp!
   net-ssh
   open4 (~> 1.3.4)
   puppet (= 3.7.1)