Update Infisical instructions to new SDK

Current documentation is using old Infisical SDK implementation.

New SDK has a different name, and authenticates on a method, not in the class constructor.

Author: fgcoelho

docs/deploy-environment-variables.mdx

@@ -103,12 +103,14 @@ export default defineConfig({
   build: {
     extensions: [
       syncEnvVars(async (ctx) => {
-        const client = new InfisicalClient({
-          clientId: process.env.INFISICAL_CLIENT_ID,
-          clientSecret: process.env.INFISICAL_CLIENT_SECRET,
+        const client = new InfisicalSDK();
+
+        await client.auth().universalAuth.login({
+          clientId: process.env.INFISICAL_CLIENT_ID!,
+          clientSecret: process.env.INFISICAL_CLIENT!,
         });
 
-        const secrets = await client.listSecrets({
+        const { secrets } = await client.secrets().listSecrets({
           environment: ctx.environment,
           projectId: process.env.INFISICAL_PROJECT_ID!,
         });