Update README.md

Author: johlju

README.md

@@ -288,7 +288,7 @@ The following opt-in flags are available:
   new error-level script analyzer rules are violated.
 - **Common Tests - Custom Script Analyzer Rules**: fail tests if any
   custom script analyzer rules are violated.
-* **Common Tests - Validate Markdown Links**: fails tests if a link in
+- **Common Tests - Validate Markdown Links**: fails tests if a link in
   a markdown file are broken.
 
 ### Using AppVeyor.psm1 with the default shared model