Attempt to make Renovate work again (#2052)

Looks that I accidentally broke Renovate with #1891. This was made under the impression of the [Renovate change to support `baseBranches` in forking-renovate] (renovatebot/renovate#36054). However, a [later Renovate change](renovatebot/renovate#35579)  seems to break that.

The plan here is to:
1. remove the regex from our `baseBranches` option - if that doesn't work then
2. just use the default branch

Author: snazy

.github/renovate.json5

@@ -30,9 +30,10 @@
 
   // Added for posterity how to let Renovate manage version-branches, assuming that release branches
   // have the `release/` prefix.
+  // BE CAREFUL WITH THIS OPTION and make sure that the changes work.
   baseBranches: [
     "main",
-    "/^release\\/1[.].*",
+    "release/1.0.x",
   ],
   additionalBranchPrefix: "{{baseBranch}}/",
   commitMessagePrefix: "{{baseBranch}}: ",