.golangci.yml: remove exclude-dirs

Neither contrib nor dependencies contain any Go code:
 - for contrib, this is the way since commit 6041f707c ("rm
   contrib/perftest");
 - for dependencies, this is the way since commit c7827957a ("ginkgo:
   restructure install work flow").

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

.golangci.yml

@@ -75,10 +75,6 @@ issues:
   # Set to 0 to disable.
   # Default: 3
   max-same-issues: 0
-  exclude-dirs-use-default: true
-  exclude-dirs:
-    - contrib
-    - dependencies
   exclude-rules:
     # Exclude recvcheck from running on the imported k8s files, to much failures
     - path: pkg/k8s.io/