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/hpack/encode.go

@@ -116,6 +116,11 @@ func (e *Encoder) SetMaxDynamicTableSize(v uint32) {
 	e.dynTab.setMaxSize(v)
 }
 
+// MaxDynamicTableSize returns the current dynamic header table size.
+func (e *Encoder) MaxDynamicTableSize() (v uint32) {
+	return e.dynTab.maxSize
+}
+
 // SetMaxDynamicTableSizeLimit changes the maximum value that can be
 // specified in SetMaxDynamicTableSize to v. By default, it is set to
 // 4096, which is the same size of the default dynamic header table