Error(s) in re-building vignettes:
--- re-building ‘bioconductor.Rmd’ using rmarkdown
--- finished re-building ‘bioconductor.Rmd’

--- re-building ‘depgraph.Rmd’ using rmarkdown
Could not fetch https://github.com/neurogenomics/rworkflows/raw/master/reports/rworkflows_depgraph.png
HttpExceptionRequest Request {
  host                 = "github.com"
  port                 = 443
  secure               = True
  requestHeaders       = []
  path                 = "/neurogenomics/rworkflows/raw/master/reports/rworkflows_depgraph.png"
  queryString          = ""
  method               = "GET"
  proxy                = Nothing
  rawBody              = False
  redirectCount        = 10
  responseTimeout      = ResponseTimeoutDefault
  requestVersion       = HTTP/1.1
}
 (InternalException (HandshakeFailed (Error_Protocol ("certificate has unknown CA",True,UnknownCa))))
Error: processing vignette 'depgraph.Rmd' failed with diagnostics:
pandoc document conversion failed with error 61
--- failed re-building ‘depgraph.Rmd’

--- re-building ‘docker.Rmd’ using rmarkdown
--- finished re-building ‘docker.Rmd’

--- re-building ‘repos.Rmd’ using rmarkdown
--- finished re-building ‘repos.Rmd’

--- re-building ‘rworkflows.Rmd’ using rmarkdown
Could not fetch https://github.com/neurogenomics/rworkflows/raw/master/inst/hex/hex.png
HttpExceptionRequest Request {
  host                 = "github.com"
  port                 = 443
  secure               = True
  requestHeaders       = []
  path                 = "/neurogenomics/rworkflows/raw/master/inst/hex/hex.png"
  queryString          = ""
  method               = "GET"
  proxy                = Nothing
  rawBody              = False
  redirectCount        = 10
  responseTimeout      = ResponseTimeoutDefault
  requestVersion       = HTTP/1.1
}
 (InternalException (HandshakeFailed (Error_Protocol ("certificate has unknown CA",True,UnknownCa))))
Error: processing vignette 'rworkflows.Rmd' failed with diagnostics:
pandoc document conversion failed with error 61
--- failed re-building ‘rworkflows.Rmd’

SUMMARY: processing the following files failed:
  ‘depgraph.Rmd’ ‘rworkflows.Rmd’

Error: Vignette re-building failed.
Execution halted