fix: remove unknown linters:

When running in CI, I obtained the following error:

```
  Running [/home/runner/golangci-lint-1.41.0-linux-amd64/golangci-lint run --out-format=github-actions --new-from-patch=/tmp/tmp-1795-28vaWZek2jfM/pull.patch --new=false --new-from-rev=] in [] ...
  level=error msg="Running error: unknown linters: 'ireturn,maintidx', run 'golangci-lint linters' to see the list of supported linters"
```

.golangci.yaml

@@ -23,13 +23,11 @@ linters:
     - exhaustivestruct
     - tagliatelle
     - godox
-    - ireturn
 
     # We should strive to enable these:
     - wrapcheck
     - dupl
     - makezero
-    - maintidx
 
     # We might want to enable this, but it might be a lot of work
     - cyclop