feat: upgrade bookstack to 0.28.2

Author: solidnerd

Diff for: Dockerfile

@@ -1,5 +1,5 @@
 FROM alpine:3 as bookstack
-ENV BOOKSTACK_VERSION=0.28.1
+ENV BOOKSTACK_VERSION=0.28.2
 RUN apk add --no-cache curl tar
 RUN set -x; \
     curl -SL -o bookstack.tar.gz https://github.com/BookStackApp/BookStack/archive/v${BOOKSTACK_VERSION}.tar.gz  \

Diff for: README.md

@@ -2,7 +2,7 @@
 
 [![Build Status](https://travis-ci.org/solidnerd/docker-bookstack.svg?branch=master)](https://travis-ci.org/solidnerd/docker-bookstack) [![](https://images.microbadger.com/badges/image/solidnerd/bookstack.svg)](https://microbadger.com/images/solidnerd/bookstack "Get your own image badge on microbadger.com") [![](https://images.microbadger.com/badges/commit/solidnerd/bookstack.svg)](https://microbadger.com/images/solidnerd/bookstack "Get your own commit badge on microbadger.com") [![](https://images.microbadger.com/badges/version/solidnerd/bookstack.svg)](https://microbadger.com/images/solidnerd/bookstack "Get your own version badge on microbadger.com") [![](https://images.microbadger.com/badges/license/solidnerd/bookstack.svg)](https://microbadger.com/images/solidnerd/bookstack "Get your own license badge on microbadger.com")
 
-## Current Version: [0.28.1](https://github.com/SolidNerd/docker-bookstack/blob/master/Dockerfile)
+## Current Version: [0.28.2](https://github.com/SolidNerd/docker-bookstack/blob/master/Dockerfile)
 
 ### Changes
 In 0.12.2 we removed `DB_PORT` . You can now specify the port via `DB_HOST` like `DB_HOST=mysql:3306`
@@ -31,7 +31,7 @@ docker run -d --name bookstack-mysql -p 3306:3306 -e MYSQL_ROOT_PASSWORD=secret
 ```
 2. BookStack Container:
 ```bash
-docker run --name my-bookstack -d --link bookstack-mysql:mysql -p 8080:80 solidnerd/bookstack:0.28.1
+docker run --name my-bookstack -d --link bookstack-mysql:mysql -p 8080:80 solidnerd/bookstack:0.28.2
 ```
 
 #### Docker 1.9+

Diff for: VERSION

@@ -1 +1 @@
-0.28.1
+0.28.2

Diff for: docker-compose.yml

@@ -11,7 +11,7 @@ services:
     - mysql-data:/var/lib/mysql
 
   bookstack:
-    image: solidnerd/bookstack:0.28.1
+    image: solidnerd/bookstack:0.28.2
     depends_on:
     - mysql
     environment: