Error strings should not be capitalized

Reported by staticcheck 2022.1.2 (v0.3.2)

See: staticcheck.io

lib/http/http.go

@@ -122,7 +122,7 @@ func useSSL(opt Options) bool {
 func NewServer(listeners, tlsListeners []net.Listener, opt Options) (Server, error) {
 	// Validate input
 	if len(listeners) == 0 && len(tlsListeners) == 0 {
-		return nil, errors.New("Can't create server without listeners")
+		return nil, errors.New("can't create server without listeners")
 	}
 
 	// Prepare TLS config
@@ -130,12 +130,12 @@ func NewServer(listeners, tlsListeners []net.Listener, opt Options) (Server, err
 
 	useSSL := useSSL(opt)
 	if (len(opt.SslCertBody) > 0) != (len(opt.SslKeyBody) > 0) {
-		err := errors.New("Need both SslCertBody and SslKeyBody to use SSL")
+		err := errors.New("need both SslCertBody and SslKeyBody to use SSL")
 		log.Fatalf(err.Error())
 		return nil, err
 	}
 	if (opt.SslCert != "") != (opt.SslKey != "") {
-		err := errors.New("Need both -cert and -key to use SSL")
+		err := errors.New("need both -cert and -key to use SSL")
 		log.Fatalf(err.Error())
 		return nil, err
 	}
@@ -156,12 +156,12 @@ func NewServer(listeners, tlsListeners []net.Listener, opt Options) (Server, err
 			Certificates: []tls.Certificate{cert},
 		}
 	} else if len(listeners) == 0 && len(tlsListeners) != 0 {
-		return nil, errors.New("No SslKey or non-tlsListeners")
+		return nil, errors.New("no SslKey or non-tlsListeners")
 	}
 
 	if opt.ClientCA != "" {
 		if !useSSL {
-			err := errors.New("Can't use --client-ca without --cert and --key")
+			err := errors.New("can't use --client-ca without --cert and --key")
 			log.Fatalf(err.Error())
 			return nil, err
 		}
@@ -172,7 +172,7 @@ func NewServer(listeners, tlsListeners []net.Listener, opt Options) (Server, err
 			return nil, err
 		}
 		if !certpool.AppendCertsFromPEM(pem) {
-			err := errors.New("Can't parse client certificate authority")
+			err := errors.New("can't parse client certificate authority")
 			log.Fatalf(err.Error())
 			return nil, err
 		}

lib/jwtutil/jwtutil.go

@@ -78,7 +78,7 @@ func Config(id, name string, claims *jws.ClaimSet, header *jws.Header, queryPara
 	result := &response{}
 	err = json.NewDecoder(strings.NewReader(s)).Decode(result)
 	if result.AccessToken == "" && err == nil {
-		err = errors.New("No AccessToken in Response")
+		err = errors.New("no AccessToken in Response")
 	}
 	if err != nil {
 		return fmt.Errorf("jwtutil: failed to get token: %w", err)

lib/rest/url.go

@@ -11,7 +11,7 @@ import (
 func URLJoin(base *url.URL, path string) (*url.URL, error) {
 	rel, err := url.Parse(path)
 	if err != nil {
-		return nil, fmt.Errorf("Error parsing %q as URL: %w", path, err)
+		return nil, fmt.Errorf("error parsing %q as URL: %w", path, err)
 	}
 	return base.ResolveReference(rel), nil
 }