Update rules/Proj0501.md

Co-authored-by: Laura Kramer <[email protected]>

Author: CptWesley

rules/Proj0501.md

@@ -10,7 +10,7 @@ license and the copyright of the onwer of the package.
 
 By default, MIT and Apache-2.0 are allowed.
 
-This rules can detect used licenses in NuGet spec files, but can not be
+This rule can detect used licenses in NuGet spec files, but can not be
 considered legal advice, nor is this documentation.
 
 ## Configure