chore: release Markdown dependency version lock (#23)

* chore: release Markdown dependency version lock

content-validator is used in:
- zendesk-editor that depends on ks-markdown which requires Markdown >= 3
- email-service that depends on email-parser which requires Markdown < 3
- realtime-translation-validator
Markdown itself is used in content validator only to render preview for the end user

* chore: release Markdown dependency version lock from setup.py also

Author: snejku

requirements.txt

@@ -1,5 +1,5 @@
 beautifulsoup4==4.4.1
-Markdown==2.6.11
+Markdown
 html2text==2014.12.29
 lxml==3.5
 parse==1.8.2

setup.py

@@ -11,7 +11,7 @@ def read(f):
 
 install_requires = [
     'aiohttp >=3, <3.4',
-    'Markdown >=2, <3',
+    'Markdown',
     'parse >=1, <2',
     'beautifulsoup4 >=4, <5',
     'lxml >=3',