Renovate: Pin the Kotlin dependency

This needs to be align with Compose and for the time being stay at
version 1.7.20, also see [1].

[1]: https://github.com/JetBrains/compose-jb/blob/master/VERSIONING.md#kotlin-compatibility

Signed-off-by: Sebastian Schuberth <[email protected]>

Author: sschuberth

renovate.json

@@ -2,5 +2,13 @@
   "$schema": "https://docs.renovatebot.com/renovate-schema.json",
   "extends": [
     "config:base"
+  ],
+  "packageRules": [
+    {
+      "matchPackageNames": [
+        "org.jetbrains.kotlin.jvm"
+      ],
+      "rangeStrategy": "pin"
+    }
   ]
 }