Updated to Alpine v3.12.0

New version v1.5.0

 * new base image [technosoft2000/alpine-base:3.12-1](https://hub.docker.com/r/technosoft2000/alpine-base/) based on Alpine 3.12.0
 * fixed `[WARNING]: Empty continuation line found in: ...` in Dockerfile
 * upgrade of [sgerrand/alpine-pkg-glibc](https://github.com/sgerrand/alpine-pkg-glibc) to version 2.32-r0
 * changed glibc compiled package (ArchLinux) `libutil-linux` to new `util-linux-libs` - see issue **Build failure in v1.4.1** #87
 * updated dependencies from `requirements.txt` and `optional-requirements.txt` - see issue **Missing jsonschema in the docker image** #90
 * changed python from `python2` to `python3`
 * allow **gevent 20.9.0** otherwise:
   - error will appear `<frozen importlib._bootstrap>:219: RuntimeWarning: greenlet.greenlet size changed, may indicate binary incompatibility. Expected 144 from C header, got 152 from PyObject`
   - see at `gevent` where the issue was known: https://github.com/gevent/gevent/issues/1260
 * added **unrar**
 * **kepubify** is not added, because Alpine Linux doesn't contains a pre-build package at the moment
 * updated Calibre **ebook-convert** from 4.13.0 to 5.3.0
 * uses `https://github.com/Technosoft2000/docker-calibre-web/releases/download/kindlegen/kindlegen_linux_2.6_i386_v2_9.tar.gz` to download Amazon kindlegen

Updated to Alpine v3.11.5

v1.4.1

Update  with actual base image and new Calibre

Amazon kindlegen_linux_2.6_i386_v2_9

Keep Amazon kindlegen_linux_2.6_i386_v2_9 available for the docker image because Amazon writes:

KindleGen is no longer available for download.

Please use Kindle Previewer to convert, preview, and validate your eBooks. Kindle Previewer provides the same functionality of KindleGen and, in addition, provides:

Latest Kindle Conversion software that provides up-to-date validation for Enhanced Typesetting books (currently available for books in all languages except Simplified Chinese, Japanese, and Russian).
Choice of using in Graphical User Interface (GUI) for a visual inspection of your book, or, Command Line Interface (CLI) mode for bulk validation.
Faster preview and validation with features like thumbnails, auto-previews, and filters for pages with images, tables, drop caps, and links.

We recommend using EPUB format for publishing new reflowable titles and updating previously published titles.
MOBI should only be used when testing on older devices that do not support Enhanced Typesetting.

Updated to Alpine v3.11.2

v1.4.0

* upgrade to new base image [technosoft2000/alpine-base:3.11-1](https…

Update release - glibc & other libs update

- upgrade of alpine-pg-glibc to 2.30-r0

- added additional glibc packages
- updated dependent libraries

Update release - glibc & other libs update

- upgrade of glibc package

- merged pull request from @ariesdevil

Ghostscript 9.26 with patches

v1.3.1

- self compiled Ghostscript 9.26 with patches

New Alpine Version 3.9

- new base image based on Alpine 3.9

- patched the 'policy.xml' of ImageMagick 6
- updated libraries

PDF conversions via ebook-convert

v1.2.3

 * added missing dependency **libxcomposite** which is needed for PDF…

Support of additional glibc locale

v1.2.2

 - glibc locale are generated now for the following definitions: [ava…