chore: Update renovate config for new haskell-cabal manager

This manager was recently introduced to renovate and is now creating PRs
for upper version bounds of our haskell dependencies. We still need to
figure out how to deal with those in the best way, but some basic
configuration can already be done. Here, we:
- disallow any of those updates on the backbranches.
- group GHC-provided dependencies together.
- group packages from the hasql ecosystem together.

.github/renovate.json

@@ -14,7 +14,20 @@
   "packageRules": [
     {
       "matchBaseBranches": [ "/^v[0-9]+/" ],
-      "groupName": "all dependencies"
+      "groupName": "all dependencies",
+      "haskell-cabal": {
+        "enabled": false
+      }
+    },
+    {
+      "matchManagers": ["haskell-cabal"],
+      "matchPackageNames": ["base", "bytestring", "containers", "directory", "mtl", "parsec", "process", "text"],
+      "groupName": "GHC dependencies"
+    },
+    {
+      "matchManagers": ["haskell-cabal"],
+      "matchPackageNames": ["hasql", "hasql-dynamic-statements", "hasql-notifications", "hasql-transaction", "hasql-pool"],
+      "groupName": "hasql"
     }
   ]
 }