Update README to reference v5 tag (#170)

https://claude.ai/code/session_01Gkro53j1ATnVLnsPkprRgf

Co-authored-by: Claude <noreply@anthropic.com>

Author: kyleconroy

README.md

@@ -7,7 +7,7 @@ This [action](https://docs.github.com/actions) downloads and installs [sqlc](htt
 ```yaml
 steps:
 # Ensure sqlc is installed
-- uses: sqlc-dev/setup-sqlc@v4
+- uses: sqlc-dev/setup-sqlc@v5
   with:
     sqlc-version: '1.25.0'
 # Print out the current version