Replace `README.md` with a notice linking to the new location.

README.md

@@ -1,85 +1,5 @@
-# certstore [![PkgGoDev](https://pkg.go.dev/badge/github.com/github/certstore?tab=doc)](https://pkg.go.dev/github.com/github/certstore?tab=doc) [![Report card](https://goreportcard.com/badge/github.com/github/certstore)](https://goreportcard.com/report/github.com/github/certstore)
+# This project has moved
 
-[![Test macOS (recent Go versions)](<https://github.com/github/certstore/workflows/Test%20macOS%20(recent%20Go%20versions)/badge.svg>)](https://github.com/github/certstore/actions?query=workflow%3A%22Test+macOS+%28recent+Go+versions%29%22)  
-[![Test Windows (recent Go versions)](<https://github.com/github/certstore/workflows/Test%20Windows%20(recent%20Go%20versions)/badge.svg>)](https://github.com/github/certstore/actions?query=workflow%3A%22Test+Windows+%28recent+Go+versions%29%22)  
+`certstore` is now part of the <https://github.com/github/smimesign> repository.
 
-Certstore is a Go library for accessing user identities stored in platform certificate stores. On Windows and macOS, certstore can enumerate user identities and sign messages with their private keys.
-
-## Example
-
-```go
-package main
-
-import (
-	"crypto"
-	"encoding/hex"
-	"errors"
-	"fmt"
-
-	"crypto/rand"
-	"crypto/sha256"
-
-	"github.com/github/certstore"
-)
-
-func main() {
-	sig, err := signWithMyIdentity("Ben Toews", "hello, world!")
-	if err != nil {
-		panic(err)
-	}
-
-	fmt.Println(hex.EncodeToString(sig))
-}
-
-func signWithMyIdentity(cn, msg string) ([]byte, error) {
-	// Open the certificate store for use. This must be Close()'ed once you're
-	// finished with the store and any identities it contains.
-	store, err := certstore.Open()
-	if err != nil {
-		return nil, err
-	}
-	defer store.Close()
-
-	// Get an Identity slice, containing every identity in the store. Each of
-	// these must be Close()'ed when you're done with them.
-	idents, err := store.Identities()
-	if err != nil {
-		return nil, err
-	}
-
-	// Iterate through the identities, looking for the one we want.
-	var me certstore.Identity
-	for _, ident := range idents {
-		defer ident.Close()
-
-		crt, errr := ident.Certificate()
-		if errr != nil {
-			return nil, errr
-		}
-
-		if crt.Subject.CommonName == "Ben Toews" {
-			me = ident
-		}
-	}
-
-	if me == nil {
-		return nil, errors.New("Couldn't find my identity")
-	}
-
-	// Get a crypto.Signer for the identity.
-	signer, err := me.Signer()
-	if err != nil {
-		return nil, err
-	}
-
-	// Digest and sign our message.
-	digest := sha256.Sum256([]byte(msg))
-	signature, err := signer.Sign(rand.Reader, digest[:], crypto.SHA256)
-	if err != nil {
-		return nil, err
-	}
-
-	return signature, nil
-}
-
-```
+Please update your dependencies from `github.com/github/certstore` to [`github.com/github/smimesign/certstore`](https://github.com/github/smimesign/tree/main/certstore)