Update nimbus-jose-jwt to 9.8.1

Issue gh-344

gradle/dependency-management.gradle

@@ -25,6 +25,7 @@ dependencyManagement {
 	}
 
 	dependencies {
+		dependency "com.nimbusds:nimbus-jose-jwt:9.8.1"
 		dependency "javax.servlet:javax.servlet-api:4.0.1"
 		dependency 'junit:junit:4.13.2'
 		dependency 'org.assertj:assertj-core:3.19.0'

oauth2-authorization-server/src/main/java/org/springframework/security/oauth2/jwt/NimbusJwsEncoder.java

@@ -43,7 +43,6 @@ import com.nimbusds.jose.util.Base64URL;
 import com.nimbusds.jwt.JWTClaimsSet;
 import com.nimbusds.jwt.SignedJWT;
 
-import net.minidev.json.JSONObject;
 import org.springframework.core.convert.converter.Converter;
 import org.springframework.util.Assert;
 import org.springframework.util.CollectionUtils;
@@ -198,7 +197,7 @@ public final class NimbusJwsEncoder implements JwtEncoder {
 			Map<String, Object> jwk = headers.getJwk();
 			if (!CollectionUtils.isEmpty(jwk)) {
 				try {
-					builder.jwk(JWK.parse(new JSONObject(jwk)));
+					builder.jwk(JWK.parse(jwk));
 				}
 				catch (Exception ex) {
 					throw new JwtEncodingException(String.format(ENCODING_ERROR_MESSAGE_TEMPLATE,