Update the docs with latest changes

[GunalanD10]

hi ,
i have followed the docs to utilise this lib , which is per documentation but getting error as we need to pass url while initializing

>>> from pycvesearch import CVESearch
>>> cve = CVESearch()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: CVESearch.__init__() missing 1 required positional argument: 'base_url'
>>> 

Versions : pycvesearch==1.0.1