[MINOR] chore: fix kubernetes ci pipeline (apache#1368)

### What changes were proposed in this pull request?

Specify the version of `goimports`.

### Why are the changes needed?

fix kubernetes ci pipeline.
https://github.com/apache/incubator-uniffle/actions/runs/7190065186/job/19582604526

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

CI passed.

deploy/kubernetes/operator/Makefile

@@ -121,7 +121,7 @@ envtest: ## Download envtest-setup locally if necessary.
 GOIMPORTS = $(LOCAL_DIR)/goimports
 .PHONY: goimports
 goimports: ## Download goimports locally if necessary.
-	$(call go-get-tool,$(GOIMPORTS),golang.org/x/tools/cmd/goimports@latest)
+	$(call go-get-tool,$(GOIMPORTS),golang.org/x/tools/cmd/goimports@v0.15.0)
 	$(GOIMPORTS) -local github.com/apache/incubator-uniffle/deploy/kubernetes/operator -w .
 
 REVIVE = $(LOCAL_DIR)/revive