re-enable import sorting in generated code

When we switched to gci, all sorting was effectively disabled, even though from the Makefile it's
clear that once "codegen" is done, "make imports" is supposed to run, hinting at a desire to have
our generated code properly sorted.

On-behalf-of: @SAP [email protected]

Author: xrstf

.golangci.yaml

@@ -92,7 +92,7 @@ linters-settings:
     - prefix(github.com/kcp-dev/kcp)
     - blank
     - dot
-    skip-generated: true
+    skip-generated: false
   gosec:
     excludes:
     - G307 # Deferring unsafe method "Close" on type "\*os.File"

Makefile

@@ -226,11 +226,11 @@ verify-codegen: ## Verify codegen
 .PHONY: imports
 imports: WHAT ?=
 imports: $(GOLANGCI_LINT) verify-go-versions
-	@if [ -n "$(WHAT)" ]; then \
-	  $(GOLANGCI_LINT) run --enable-only=gci --fix --fast $(WHAT); \
+	if [ -n "$(WHAT)" ]; then \
+	  $(GOLANGCI_LINT) run --enable-only=gci --fix --exclude-generated disable $(WHAT); \
 	else \
 	  for MOD in . $$(git ls-files '**/go.mod' | sed 's,/go.mod,,'); do \
-		(cd $$MOD; $(GOLANGCI_LINT) run --enable-only=gci --fix --fast); \
+		(set -x; cd $$MOD; $(GOLANGCI_LINT) run --enable-only=gci --fix --exclude-generated disable); \
 	  done; \
 	fi