feat: upgrade bookstack to 0.30.4 (#217)

Author: solidnerd

Diff for: Dockerfile

@@ -1,5 +1,5 @@
 FROM alpine:3 as bookstack
-ENV BOOKSTACK_VERSION=0.30.2
+ENV BOOKSTACK_VERSION=0.30.4
 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: [0.30.2](https://github.com/SolidNerd/docker-bookstack/blob/master/Dockerfile)
+## Current Version: [0.30.4](https://github.com/SolidNerd/docker-bookstack/blob/master/Dockerfile)
 
 ### Changes
 
@@ -49,8 +49,8 @@ mysql:5.7.21
 ```bash
 docker run -d --link bookstack_db_:mysql \
 -p 8080:8080 \
---name bookstack_0.30.2 \
-solidnerd/bookstack:0.30.2
+--name bookstack_0.30.4 \
+solidnerd/bookstack:0.30.4
 ```
 
 #### Docker 1.9+
@@ -82,8 +82,8 @@ docker run -d --net bookstack_nw \
 -e DB_USERNAME=bookstack \
 -e DB_PASSWORD=secret \
 -p 8080:8080 \
---name="bookstack_0.30.2" \
- solidnerd/bookstack:0.30.2
+--name="bookstack_0.30.4" \
+ solidnerd/bookstack:0.30.4
 ```
 
 #### Volumes

Diff for: VERSION

@@ -1 +1 @@
-0.30.2
+0.30.4

Diff for: docker-compose.yml

@@ -11,7 +11,7 @@ services:
     - mysql-data:/var/lib/mysql
 
   bookstack:
-    image: solidnerd/bookstack:0.30.2
+    image: solidnerd/bookstack:0.30.4
     depends_on:
     - mysql
     environment: