Use debug instead of trace

Trace outputs stack traces which is entirely unnecessary for these two
log entries and makes the logs noisier than they need to be.

src/node/heart.ts

@@ -31,7 +31,7 @@ export class Heart {
       return
     }
 
-    logger.trace("heartbeat")
+    logger.debug("heartbeat")
     this.lastHeartbeat = Date.now()
     if (typeof this.heartbeatTimer !== "undefined") {
       clearTimeout(this.heartbeatTimer)

src/node/main.ts

@@ -109,7 +109,7 @@ export const runCodeServer = async (
   logger.info(`code-server ${version} ${commit}`)
 
   logger.info(`Using user-data-dir ${args["user-data-dir"]}`)
-  logger.trace(`Using extensions-dir ${args["extensions-dir"]}`)
+  logger.debug(`Using extensions-dir ${args["extensions-dir"]}`)
 
   if (args.auth === AuthType.Password && !args.password && !args["hashed-password"]) {
     throw new Error(