add the stylecheck linter

internal/wire/header.go

@@ -215,9 +215,11 @@ func (h *Header) parseLongHeader(b *bytes.Reader) error {
 
 func (h *Header) parseVersionNegotiationPacket(b *bytes.Reader) error {
 	if b.Len() == 0 {
+		//nolint:stylecheck
 		return errors.New("Version Negotiation packet has empty version list")
 	}
 	if b.Len()%4 != 0 {
+		//nolint:stylecheck
 		return errors.New("Version Negotiation packet has a version list with an invalid length")
 	}
 	h.SupportedVersions = make([]protocol.VersionNumber, b.Len()/4)

internal/wire/new_connection_id_frame.go

@@ -32,6 +32,7 @@ func parseNewConnectionIDFrame(r *bytes.Reader, _ protocol.VersionNumber) (*NewC
 		return nil, err
 	}
 	if ret > seq {
+		//nolint:stylecheck
 		return nil, fmt.Errorf("Retire Prior To value (%d) larger than Sequence Number (%d)", ret, seq)
 	}
 	connIDLen, err := r.ReadByte()

internal/wire/new_token_frame.go

@@ -26,7 +26,7 @@ func parseNewTokenFrame(r *bytes.Reader, _ protocol.VersionNumber) (*NewTokenFra
 		return nil, io.EOF
 	}
 	if tokenLen == 0 {
-		return nil, errors.New("Token must not be empty.")
+		return nil, errors.New("token must not be empty")
 	}
 	token := make([]byte, int(tokenLen))
 	if _, err := io.ReadFull(r, token); err != nil {

internal/wire/new_token_frame_test.go

@@ -29,7 +29,7 @@ var _ = Describe("NEW_TOKEN frame", func() {
 			data = append(data, encodeVarInt(uint64(0))...)
 			b := bytes.NewReader(data)
 			_, err := parseNewTokenFrame(b, protocol.VersionWhatever)
-			Expect(err).To(MatchError("Token must not be empty."))
+			Expect(err).To(MatchError("token must not be empty"))
 		})
 
 		It("errors on EOFs", func() {