`plot.GRiwrm` not working in gitlab-ci

Here the errors we have on check:

--- re-building ‘V01_Structure_SD_model.Rmd’ using rmarkdown
Quitting from lines 78-80 (V01_Structure_SD_model.Rmd) 
Error: processing vignette 'V01_Structure_SD_model.Rmd' failed with diagnostics:
invalid value 0 for 'digits' argument
--- failed re-building ‘V01_Structure_SD_model.Rmd’
--- re-building ‘V02_Calibration_SD_model.Rmd’ using rmarkdown
--- finished re-building ‘V02_Calibration_SD_model.Rmd’
--- re-building ‘V03_Open-loop_influenced_flow.Rmd’ using rmarkdown
Quitting from lines 64-65 (V03_Open-loop_influenced_flow.Rmd) 
Error: processing vignette 'V03_Open-loop_influenced_flow.Rmd' failed with diagnostics:
invalid value 0 for 'digits' argument
--- failed re-building ‘V03_Open-loop_influenced_flow.Rmd’
--- re-building ‘V04_Closed-loop_regulated_withdrawal.Rmd’ using rmarkdown
Quitting from lines 58-69 (V04_Closed-loop_regulated_withdrawal.Rmd) 
Error: processing vignette 'V04_Closed-loop_regulated_withdrawal.Rmd' failed with diagnostics:
invalid value 0 for 'digits' argument
--- failed re-building ‘V04_Closed-loop_regulated_withdrawal.Rmd’
--- re-building ‘airgriwrm.Rmd’ using rmarkdown
--- finished re-building ‘airgriwrm.Rmd’