Fix error on metadata read

[zerasul]

Traceback (most recent call last):
File "e:\development\persweb\mkdocs\venv\lib\site-packages\flask\app.py", line 2446, in wsgi_app
response = self.full_dispatch_request()
File "e:\development\persweb\mkdocs\venv\lib\site-packages\flask\app.py", line 1951, in full_dispatch_request
rv = self.handle_user_exception(e)
File "e:\development\persweb\mkdocs\venv\lib\site-packages\flask\app.py", line 1820, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "e:\development\persweb\mkdocs\venv\lib\site-packages\flask_compat.py", line 39, in reraise
raise value
File "e:\development\persweb\mkdocs\venv\lib\site-packages\flask\app.py", line 1949, in full_dispatch_request
rv = self.dispatch_request()
File "e:\development\persweb\mkdocs\venv\lib\site-packages\flask\app.py", line 1935, in dispatch_request
return self.view_functionsrule.endpoint
File "e:\development\persweb\mkdocs\venv\lib\site-packages\Blask\blaskapp.py", line 73, in _getpage
entry = self.blogrenderer.renderfile(filename)
File "e:\development\persweb\mkdocs\venv\lib\site-packages\Blask\blogrenderer.py", line 71, in renderfile
entry = self.rendertext(filename, content)
File "e:\development\persweb\mkdocs\venv\lib\site-packages\Blask\blogrenderer.py", line 84, in rendertext
entry = BlogEntry(filename, md, text)
File "e:\development\persweb\mkdocs\venv\lib\site-packages\Blask\blogrenderer.py", line 171, in init
self.date = datetime.strptime(meta["date"][0], "%Y-%m-%d")