updated README.rst , added hyperlink to banner

[itsAftabAlam]

updated README.rst , added hyperlink to banner , please check it might be beneficial
closes #5283

[codecov]

Codecov Report

Merging #5284 (42ddb81) into master (afa5881) will decrease coverage by 0.01%.
The diff coverage is n/a.

❗ Current head 42ddb81 differs from pull request most recent head 4d32ed3. Consider uploading reports for the commit 4d32ed3 to get more accurate results

@@            Coverage Diff             @@
##           master    #5284      +/-   ##
==========================================
- Coverage   88.52%   88.51%   -0.02%     
==========================================
  Files         163      163              
  Lines       10610    10610              
  Branches     1557     1557              
==========================================
- Hits         9393     9391       -2     
- Misses        942      943       +1     
- Partials      275      276       +1     

Impacted Files	Coverage Δ
scrapy/core/downloader/__init__.py	90.97% <0.00%> (-1.51%)	⬇️

[kmike]

Thanks @itsAftabAlam!