fix: add important message to readme that show incompatibility with c… (#1028)

* fix: add important message to readme that show incompatibility with certain go version

Author: panavenue

README.md

@@ -39,6 +39,14 @@ guide](./migration-guide.md).
 
 For a quick example, try out the Go Connector in a [Codelab][codelab].
 
+
+> [!WARNING]
+> **Go versions 1.25.2 and 1.24.8 are NOT compatible with Cloud SQL Go Connector.**
+>
+> A recent update to the Go version 1.25.2 and Go 1.24.8 breaks SAN verificaton in Go Connector. This is because Cloud SQL includes a trailing dot in the DNS name within the certificate's Subject Alternative Name (SAN), which the above Go versions reject as a malformed DNS name.
+>
+> For more details, please see the related Go issue: [crypto/x509: quadratic complexity when checking name constraints ](https://github.com/golang/go/issues/75715).
+
 ## Installation
 
 You can install this repo with `go get`: