Bump github.com/MicahParks/keyfunc from 1.5.1 to 1.9.0

Bumps [github.com/MicahParks/keyfunc](https://github.com/MicahParks/keyfunc) from 1.5.1 to 1.9.0.
- [Release notes](https://github.com/MicahParks/keyfunc/releases)
- [Commits](https://github.com/MicahParks/keyfunc/compare/v1.5.1...v1.9.0)

---
updated-dependencies:
- dependency-name: github.com/MicahParks/keyfunc
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

vendor/github.com/MicahParks/keyfunc/keyfunc.go

@@ -16,16 +16,33 @@ var (
 
 // Keyfunc matches the signature of github.com/golang-jwt/jwt/v4's jwt.Keyfunc function.
 func (j *JWKS) Keyfunc(token *jwt.Token) (interface{}, error) {
+	kid, alg, err := kidAlg(token)
+	if err != nil {
+		return nil, err
+	}
+	return j.getKey(alg, kid)
+}
+
+func (m *MultipleJWKS) Keyfunc(token *jwt.Token) (interface{}, error) {
+	return m.keySelector(m, token)
+}
+
+func kidAlg(token *jwt.Token) (kid, alg string, err error) {
 	kidInter, ok := token.Header["kid"]
 	if !ok {
-		return nil, fmt.Errorf("%w: could not find kid in JWT header", ErrKID)
+		return "", "", fmt.Errorf("%w: could not find kid in JWT header", ErrKID)
 	}
-	kid, ok := kidInter.(string)
+	kid, ok = kidInter.(string)
 	if !ok {
-		return nil, fmt.Errorf("%w: could not convert kid in JWT header to string", ErrKID)
+		return "", "", fmt.Errorf("%w: could not convert kid in JWT header to string", ErrKID)
 	}
-
-	return j.getKey(kid)
+	alg, ok = token.Header["alg"].(string)
+	if !ok {
+		// For test coverage purposes, this should be impossible to reach because the JWT package rejects a token
+		// without an alg parameter in the header before calling jwt.Keyfunc.
+		return "", "", fmt.Errorf(`%w: the JWT header did not contain the "alg" parameter, which is required by RFC 7515 section 4.1.1`, ErrJWKAlgMismatch)
+	}
+	return kid, alg, nil
 }
 
 // base64urlTrailingPadding removes trailing padding before decoding a string from base64url. Some non-RFC compliant