Update README.md

Author: kyleconroy

README.md

@@ -7,9 +7,9 @@ This [action](https://docs.github.com/actions) downloads and installs [sqlc](htt
 ```yaml
 steps:
 # Ensure sqlc is installed
-- uses: sqlc-dev/setup-sqlc@v3
+- uses: sqlc-dev/setup-sqlc@v4
   with:
-    sqlc-version: '1.20.0'
+    sqlc-version: '1.21.0'
 # Print out the current version
 - run: sqlc version
 ```