fix: update README for library conversion to microgenerator (#29)

* update README

* update version

* Update README.rst

Co-authored-by: Bu Sun Kim <8822365+busunkim96@users.noreply.github.com>

Co-authored-by: Bu Sun Kim <8822365+busunkim96@users.noreply.github.com>

packages/google-cloud-webrisk/README.rst

@@ -32,6 +32,16 @@ In order to use this library, you first need to go through the following steps:
 .. _Enable the Web Risk API.:  https://cloud.google.com/web-risk
 .. _Setup Authentication.: https://googleapis.dev/python/google-api-core/latest/auth.html
 
+Supported Python Versions
+^^^^^^^^^^^^^^^^^^^^^^^^^
+Python >= 3.6
+
+Deprecated Python Versions
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+Python == 2.7.
+
+The last version of this library compatible with Python 2.7 is google-cloud-webrisk==0.3.0 
+
 Installation
 ~~~~~~~~~~~~