lint: Ignore 'dotfiles' warnings in test/

This allows to keep using
```
import (
	. "github.com/onsi/gomega"
	. "github.com/onsi/ginkgo/v2"
)
```

Unfortunately this also allows to use
```
import . "fmt"
```

I haven't been able to make the ignore rule more fine-grained.
I don't expect this will happen though.

Allowing to use non-namespaced `gomega` and `ginkgo` API calls should
make writing tests more convenient/more readable.

.golangci.yml

@@ -14,3 +14,10 @@ linters:
     - unused
     - misspell
     - revive
+
+issues:
+  exclude-rules:
+    - path: 'test/*'
+      text: 'dot-imports: should not use dot imports'
+      linters:
+        - revive