fix: increase fallbackSecondaryRateRetryAfter to new default value of 60

The secondary rate limit default value in `@octokit/plugin-throttling` was increased to 60 in version 5. However, because we are still using an older version, we manually set the option here. Hopefully fixes intuit#2458.

packages/core/src/git.ts

@@ -139,6 +139,7 @@ export default class Git {
       previews: ["symmetra-preview"],
       request: { agent: this.options.agent },
       throttle: {
+        fallbackSecondaryRateRetryAfter: 60,
         /** Add a wait once rate limit is hit */
         onRateLimit: (retryAfter: number, opts: ThrottleOpts) => {
           this.logger.log.warn(