fix(deps): update dependency openid-client to v6

package.json

@@ -52,7 +52,7 @@
     "long": "5.3.2",
     "nice-grpc": "2.1.17",
     "node-rsa": "2.0.0",
-    "openid-client": "5.7.1",
+    "openid-client": "6.8.8",
     "protobufjs": "8.8.0"
   }
 }

src/credentials/service-account.ts

@@ -1,6 +1,6 @@
 import { importPKCS8, SignJWT } from 'jose';
 import NodeRSA from 'node-rsa';
-import { Issuer, TokenSet } from 'openid-client';
+import { discovery, type TokenEndpointResponse } from 'openid-client';
 
 type ServiceAccountJson = {
   userId: string;
@@ -156,12 +156,12 @@ export class ServiceAccount {
   public async authenticate(audience: string, options?: AuthenticationOptions): Promise<string> {
     const { default: axios } = await import('axios');
 
-    const issuer = await Issuer.discover(audience);
-    const tokenEndpoint = issuer.metadata.token_endpoint ?? 'N/A';
+    const config = await discovery(new URL(audience), this.userId);
+    const tokenEndpoint = config.serverMetadata().token_endpoint ?? 'N/A';
 
     const jwt = await this.getSignedJwt(audience);
 
-    const response = await axios.post<TokenSet>(
+    const response = await axios.post<TokenEndpointResponse>(
       tokenEndpoint,
       new URLSearchParams({
         assertion: jwt,