docs: Fix URL in README.md (#1483)

missing closing url paren

README.md

diff --git a/README.md b/README.md
index 10c7d0a..6ac8b7b 100644
--- a/README.md
+++ b/README.md
@@ -216,7 +216,7 @@
 Using PyPI packages (aka "pip install") involves two main steps.
 
 1. [Installing third_party packages](#installing-third_party-packages)
-2. [Using third_party packages as dependencies](#using-third_party-packages-as-dependencies
+2. [Using third_party packages as dependencies](#using-third_party-packages-as-dependencies)
 
 ### Installing third_party packages