chore(deps): enable Renovate updates for indirect Go modules (#972)

## Summary

- Renovate's `gomod` manager [disables indirect-dep updates by
default](https://docs.renovatebot.com/modules/manager/gomod/). The
existing `go-indirect` rule sets a `groupName` but never flips
`enabled`, so indirect deps never get PRs.
- Set `"enabled": true` on that rule.

#971 is the manual catch-up for deps that have been dormant under this
rule.

Author: cpcloud

renovate.json

@@ -21,7 +21,8 @@
       "description": "Group all indirect Go dependencies",
       "matchManagers": ["gomod"],
       "matchDepTypes": ["indirect"],
-      "groupName": "go-indirect"
+      "groupName": "go-indirect",
+      "enabled": true
     },
     {
       "description": "Group GitHub Actions updates",