title: Change output width of plotly chart size in R Markdown PDF output
body: <p>On a R markdown file, does someone know why <code>out.width</code>,<code>out.height</code>,<code>figure.width</code> and <code>figure.height</code> parameters doesn't change plotly charts size when producing a pdf file? ( I precise that such parameters works perfectly using <code>plot</code> function) </p>
  
  <p><strong>Please find below a reproductible example with a Rmarkdown file</strong></p>
  
  <p>On this example, I would like the plotly chart to occupy the entire sheet like the plot chart. </p>
  
  <pre><code>---
  title: "Change chart size chart on pdf file using plotly"
  output:
    pdf_document: default
  ---
  
  ```{r setup, include = FALSE}
  knitr::opts_chunk$set(echo=FALSE,message=FALSE)
  
  ```
  
  ## Parameters doesn't work with plotly  
  
  ```{r, out.width='100%',out.height='100%',fig.height=20, fig.width=15, fig.align="left"}
  library(plotly)
  plot_ly(x = cars[1:10,]$speed,y = cars[1:10,]$dist)
  ```
  
  ## Parameters works using plot function
  
  ```{r,out.width='130%',out.height='100%', fig.height=20, fig.width=15, fig.align="left"}
  plot(cars[1:10,])
  ```
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/hT1Fr.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/hT1Fr.png" alt="enter image description here"></a></p>