update README

Author: wroge

README.md

@@ -1,7 +1,9 @@
+[![go.dev reference](https://img.shields.io/badge/go.dev-reference-007d9c?logo=go&logoColor=white)](https://pkg.go.dev/github.com/wroge/sqlt@v0.2.0-alpha.13)
+
 ## WGS84 - Coordinate Transformations
 
 ```
-github.com/wroge/wgs84/v2
+go get github.com/wroge/wgs84/v2@v2.0.0-alpha.13
 ```