shim: support -min-version and -max-version

Required for test case RSA-PSS-Default-Sign which is currently the only
test that fails with tls-tris.

tls_shim.go

@@ -19,6 +19,8 @@ func main() {
 		keyFile     = fs.String("key-file", "", "")
 		certFile    = fs.String("cert-file", "", "")
 		resumeCount = fs.Int("resume-count", 0, "")
+		minVersion  = fs.Int("min-version", tls.VersionSSL30, "")
+		maxVersion  = fs.Int("max-version", tls.VersionTLS13, "")
 	)
 
 	fmt.Println("Args:", os.Args[1:])
@@ -39,8 +41,8 @@ func main() {
 	}
 
 	config := &tls.Config{
-		MinVersion:         tls.VersionSSL30,
-		MaxVersion:         tls.VersionTLS13,
+		MinVersion:         uint16(*minVersion),
+		MaxVersion:         uint16(*maxVersion),
 		InsecureSkipVerify: true,
 	}