Fix badge formatting in README.md

Author: rogerwelin

README.md

@@ -1,7 +1,7 @@
 # pg_column_tetris
 
 [![PostgreSQL](https://img.shields.io/badge/PostgreSQL-14--18-blue.svg)](https://www.postgresql.org/)
-![GitHub Actions Workflow Status](https://img.shields.io/github/actions/workflow/status/rogerwelin/pg_column_tetris/test.yml)'
+![GitHub Actions Workflow Status](https://img.shields.io/github/actions/workflow/status/rogerwelin/pg_column_tetris/test.yml)
 
 
 A PostgreSQL extension that enforces optimal column alignment to minimize row padding waste.