[chore]: Bump github.com/microcosm-cc/bluemonday from 1.0.20 to 1.0.21 (#1004)

Bumps [github.com/microcosm-cc/bluemonday](https://github.com/microcosm-cc/bluemonday) from 1.0.20 to 1.0.21.
- [Release notes](https://github.com/microcosm-cc/bluemonday/releases)
- [Commits](https://github.com/microcosm-cc/bluemonday/compare/v1.0.20...v1.0.21)

---
updated-dependencies:
- dependency-name: github.com/microcosm-cc/bluemonday
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

vendor/golang.org/x/net/internal/socket/mmsghdr_unix.go

@@ -172,7 +172,23 @@ type mmsgTmpsPool struct {
 }
 
 func (p *mmsgTmpsPool) Get() *mmsgTmps {
-	return p.p.Get().(*mmsgTmps)
+	m := p.p.Get().(*mmsgTmps)
+	// Clear fields up to the len (not the cap) of the slice,
+	// assuming that the previous caller only used that many elements.
+	for i := range m.packer.sockaddrs {
+		m.packer.sockaddrs[i] = 0
+	}
+	m.packer.sockaddrs = m.packer.sockaddrs[:0]
+	for i := range m.packer.vs {
+		m.packer.vs[i] = iovec{}
+	}
+	m.packer.vs = m.packer.vs[:0]
+	for i := range m.packer.hs {
+		m.packer.hs[i].Len = 0
+		m.packer.hs[i].Hdr = msghdr{}
+	}
+	m.packer.hs = m.packer.hs[:0]
+	return m
 }
 
 func (p *mmsgTmpsPool) Put(tmps *mmsgTmps) {

vendor/golang.org/x/net/internal/socket/msghdr_linux.go

@@ -17,9 +17,6 @@ func (h *msghdr) pack(vs []iovec, bs [][]byte, oob []byte, sa []byte) {
 	if sa != nil {
 		h.Name = (*byte)(unsafe.Pointer(&sa[0]))
 		h.Namelen = uint32(len(sa))
-	} else {
-		h.Name = nil
-		h.Namelen = 0
 	}
 }