renovate: we're back on main now

Run renovate against docs directory on version-2. (Technically this
isn't that important because when we build the v2 docs, we do it by
importing them into the v3 docs, but it can be nice to be able to switch
to the `version-2` branch and build them directly.)

renovate.json5

@@ -2,12 +2,6 @@
   "extends": [
     "apollo-open-source"
   ],
-  /* During the last stages of v3, we are running Renovate against
-   * release-3.0 instead of main. Note that Renovate config still lives
-   * on main! Also for now let's run Renovate as much as possible rather
-   * than batching on the weekends like apollo-open-source does.
-   */
-  "baseBranches": ["release-3.0"],
   "schedule": null,
   // Disable circleci manager; see apollographql/federation's renovate file for details.
   "enabledManagers": ["npm"],
@@ -43,7 +37,7 @@
       // of Apollo Server.  "Past" major versions should be added here!
       "baseBranches": [
         "main",
-        "release-3.0"
+        "version-2"
       ]
     },
     // The current Apollo Gatsby theme does not support a version of Gatsby