title: openxlsx::write.xlsx overwriting existing worksheet instead append
body: <p>The <code>openxlsx::write.xlsx</code> function is overwriting spreadsheet instead of adding another tab.</p>
  
  <p>I tried do follow some orientations of Stackoverflow, but without sucess.</p>
  
  <pre><code>dt.escrita &lt;- format(Sys.time(), '%Y%m%d%H%M%S')
  
  write.xlsx( tbl.messages
             ,file = paste('.\\2_Datasets\\messages_',dt.escrita,'.xlsx')
             ,sheetName = format(Sys.time(), '%d-%m-%y')
             ,append = FALSE)
  
  write.xlsx( tbl.dic.dados
              ,file = paste('.\\2_Datasets\\messages_',dt.escrita,'.xlsx')
              ,sheetName = 'Dicionario_Dados'
              ,append = TRUE)
  </code></pre>
  
  <p>A spreadsheet with two tabs named: 30-07-19 and Dicionario_Dados.</p>