docs: Use a maintained fork for kubernetes-json-schema in the example

The `instrumenta/kubernetes-json-schema` repo is apparently dead:
instrumenta/kubernetes-json-schema#32 (comment)
And nobody has the credentials anymore to archive it:
instrumenta/kubeval#268 (comment)
The recommended migration from instrumenta is to https://github.com/yannh/kubeconform,
see (instrumenta/kubernetes-json-schema#32 (comment))
and the recommended `kubernetes-json-schema` fork is also from the same new maintainer:
https://github.com/yannh/kubernetes-json-schema/

Signed-off-by: Ferenc Géczi <ferenc.gm@gmail.com>

doc/configs.md

@@ -12148,7 +12148,7 @@ require('lspconfig').yamlls.setup {
     yaml = {
       ... -- other settings. note this overrides the lspconfig defaults.
       schemas = {
-        ["https://raw.githubusercontent.com/instrumenta/kubernetes-json-schema/master/v1.18.0-standalone-strict/all.json"] = "/*.k8s.yaml",
+        ["https://raw.githubusercontent.com/yannh/kubernetes-json-schema/refs/heads/master/v1.32.1-standalone-strict/all.json"] = "/*.k8s.yaml",
         ... -- other schemas
       },
     },