Bump github.com/cloudflare/circl from 1.6.0 to 1.6.1

Bumps [github.com/cloudflare/circl](https://github.com/cloudflare/circl) from 1.6.0 to 1.6.1.
- [Release notes](https://github.com/cloudflare/circl/releases)
- [Commits](https://github.com/cloudflare/circl/compare/v1.6.0...v1.6.1)

---
updated-dependencies:
- dependency-name: github.com/cloudflare/circl
  dependency-version: 1.6.1
  dependency-type: indirect
...

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

vendor/github.com/cloudflare/circl/ecc/goldilocks/curve.go

@@ -18,6 +18,9 @@ func (Curve) Identity() *Point {
 func (Curve) IsOnCurve(P *Point) bool {
 	x2, y2, t, t2, z2 := &fp.Elt{}, &fp.Elt{}, &fp.Elt{}, &fp.Elt{}, &fp.Elt{}
 	rhs, lhs := &fp.Elt{}, &fp.Elt{}
+	// Check z != 0
+	eq0 := !fp.IsZero(&P.z)
+
 	fp.Mul(t, &P.ta, &P.tb)  // t = ta*tb
 	fp.Sqr(x2, &P.x)         // x^2
 	fp.Sqr(y2, &P.y)         // y^2
@@ -27,13 +30,14 @@ func (Curve) IsOnCurve(P *Point) bool {
 	fp.Mul(rhs, t2, &paramD) // dt^2
 	fp.Add(rhs, rhs, z2)     // z^2 + dt^2
 	fp.Sub(lhs, lhs, rhs)    // x^2 + y^2 - (z^2 + dt^2)
-	eq0 := fp.IsZero(lhs)
+	eq1 := fp.IsZero(lhs)
 
 	fp.Mul(lhs, &P.x, &P.y) // xy
 	fp.Mul(rhs, t, &P.z)    // tz
 	fp.Sub(lhs, lhs, rhs)   // xy - tz
-	eq1 := fp.IsZero(lhs)
-	return eq0 && eq1
+	eq2 := fp.IsZero(lhs)
+
+	return eq0 && eq1 && eq2
 }
 
 // Generator returns the generator point.

vendor/github.com/cloudflare/circl/sign/ed25519/point.go

@@ -164,7 +164,7 @@ func (P *pointR1) isEqual(Q *pointR1) bool {
 	fp.Mul(r, r, &P.z)
 	fp.Sub(l, l, r)
 	b = b && fp.IsZero(l)
-	return b
+	return b && !fp.IsZero(&P.z) && !fp.IsZero(&Q.z)
 }
 
 func (P *pointR3) neg() {