test: set dummy value for NUGET_PACKAGES (#8107)

Signed-off-by: nikpivkin <nikita.pivkin@smartforce.io>

integration/repo_test.go

@@ -16,6 +16,7 @@ import (
 
 // TestRepository tests `trivy repo` with the local code repositories
 func TestRepository(t *testing.T) {
+	t.Setenv("NUGET_PACKAGES", t.TempDir())
 	type args struct {
 		scanner        types.Scanner
 		ignoreIDs      []string