golangci: enable 'unused' and disable deprecated replaced by it (#1983)

.golangci.yml

@@ -19,7 +19,7 @@ linters:
   disable-all: true
   enable:
     #- bodyclose
-    - deadcode
+    # - deadcode ! deprecated since v1.49.0; replaced by 'unused'
     #- depguard
     #- dogsled
     #- dupl
@@ -51,12 +51,12 @@ linters:
     #- rowserrcheck
     #- scopelint
     #- staticcheck
-    - structcheck
+    #- structcheck ! deprecated since v1.49.0; replaced by 'unused'
     #- stylecheck
     #- typecheck
     - unconvert
     #- unparam
-    #- unused
-    - varcheck
+    - unused
+    # - varcheck ! deprecated since v1.49.0; replaced by 'unused'
     #- whitespace
   fast: false