add CI tests badge

Author: jvmvik

README.md

@@ -1,4 +1,6 @@
 # User guide
+[![SerpApi-Python](https://github.com/serpapi/serpapi-python/actions/workflows/ci.yml/badge.svg)](https://github.com/serpapi/serpapi-python/actions/workflows/ci.yml)
+
 [SerpApi]](https://serpapi.com) allows to scrape any search engine results. 
  It's easy, fast, easy, feature rich, cost effective, scalable and reliable.
 

README.md.erb

@@ -8,6 +8,8 @@ def snippet(format, path, start, stop)
 end
 -%>
 # User guide
+[![SerpApi-Python](https://github.com/serpapi/serpapi-python/actions/workflows/ci.yml/badge.svg)](https://github.com/serpapi/serpapi-python/actions/workflows/ci.yml)
+
 [SerpApi]](https://serpapi.com) allows to scrape any search engine results. 
  It's easy, fast, easy, feature rich, cost effective, scalable and reliable.