rebase: bump golang.org/x/crypto from 0.3.0 to 0.4.0

Bumps [golang.org/x/crypto](https://github.com/golang/crypto) from 0.3.0 to 0.4.0.
- [Release notes](https://github.com/golang/crypto/releases)
- [Commits](https://github.com/golang/crypto/compare/v0.3.0...v0.4.0)

---
updated-dependencies:
- dependency-name: golang.org/x/crypto
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/golang.org/x/net/http2/server.go

@@ -98,6 +98,19 @@ type Server struct {
 	// the HTTP/2 spec's recommendations.
 	MaxConcurrentStreams uint32
 
+	// MaxDecoderHeaderTableSize optionally specifies the http2
+	// SETTINGS_HEADER_TABLE_SIZE to send in the initial settings frame. It
+	// informs the remote endpoint of the maximum size of the header compression
+	// table used to decode header blocks, in octets. If zero, the default value
+	// of 4096 is used.
+	MaxDecoderHeaderTableSize uint32
+
+	// MaxEncoderHeaderTableSize optionally specifies an upper limit for the
+	// header compression table used for encoding request headers. Received
+	// SETTINGS_HEADER_TABLE_SIZE settings are capped at this limit. If zero,
+	// the default value of 4096 is used.
+	MaxEncoderHeaderTableSize uint32
+
 	// MaxReadFrameSize optionally specifies the largest frame
 	// this server is willing to read. A valid value is between
 	// 16k and 16M, inclusive. If zero or otherwise invalid, a
@@ -170,6 +183,20 @@ func (s *Server) maxConcurrentStreams() uint32 {
 	return defaultMaxStreams
 }
 
+func (s *Server) maxDecoderHeaderTableSize() uint32 {
+	if v := s.MaxDecoderHeaderTableSize; v > 0 {
+		return v
+	}
+	return initialHeaderTableSize
+}
+
+func (s *Server) maxEncoderHeaderTableSize() uint32 {
+	if v := s.MaxEncoderHeaderTableSize; v > 0 {
+		return v
+	}
+	return initialHeaderTableSize
+}
+
 // maxQueuedControlFrames is the maximum number of control frames like
 // SETTINGS, PING and RST_STREAM that will be queued for writing before
 // the connection is closed to prevent memory exhaustion attacks.
@@ -394,7 +421,6 @@ func (s *Server) ServeConn(c net.Conn, opts *ServeConnOpts) {
 		advMaxStreams:               s.maxConcurrentStreams(),
 		initialStreamSendWindowSize: initialWindowSize,
 		maxFrameSize:                initialMaxFrameSize,
-		headerTableSize:             initialHeaderTableSize,
 		serveG:                      newGoroutineLock(),
 		pushEnabled:                 true,
 		sawClientPreface:            opts.SawClientPreface,
@@ -424,12 +450,13 @@ func (s *Server) ServeConn(c net.Conn, opts *ServeConnOpts) {
 	sc.flow.add(initialWindowSize)
 	sc.inflow.add(initialWindowSize)
 	sc.hpackEncoder = hpack.NewEncoder(&sc.headerWriteBuf)
+	sc.hpackEncoder.SetMaxDynamicTableSizeLimit(s.maxEncoderHeaderTableSize())
 
 	fr := NewFramer(sc.bw, c)
 	if s.CountError != nil {
 		fr.countError = s.CountError
 	}
-	fr.ReadMetaHeaders = hpack.NewDecoder(initialHeaderTableSize, nil)
+	fr.ReadMetaHeaders = hpack.NewDecoder(s.maxDecoderHeaderTableSize(), nil)
 	fr.MaxHeaderListSize = sc.maxHeaderListSize()
 	fr.SetMaxReadFrameSize(s.maxReadFrameSize())
 	sc.framer = fr
@@ -559,7 +586,6 @@ type serverConn struct {
 	streams                     map[uint32]*stream
 	initialStreamSendWindowSize int32
 	maxFrameSize                int32
-	headerTableSize             uint32
 	peerMaxHeaderListSize       uint32            // zero means unknown (default)
 	canonHeader                 map[string]string // http2-lower-case -> Go-Canonical-Case
 	writingFrame                bool              // started writing a frame (on serve goroutine or separate)
@@ -864,6 +890,7 @@ func (sc *serverConn) serve() {
 			{SettingMaxFrameSize, sc.srv.maxReadFrameSize()},
 			{SettingMaxConcurrentStreams, sc.advMaxStreams},
 			{SettingMaxHeaderListSize, sc.maxHeaderListSize()},
+			{SettingHeaderTableSize, sc.srv.maxDecoderHeaderTableSize()},
 			{SettingInitialWindowSize, uint32(sc.srv.initialStreamRecvWindowSize())},
 		},
 	})
@@ -1661,7 +1688,6 @@ func (sc *serverConn) processSetting(s Setting) error {
 	}
 	switch s.ID {
 	case SettingHeaderTableSize:
-		sc.headerTableSize = s.Val
 		sc.hpackEncoder.SetMaxDynamicTableSize(s.Val)
 	case SettingEnablePush:
 		sc.pushEnabled = s.Val != 0