title: format year-month to POSIXct
body: <p>I have some data in year-month form that I want to format for graphing in <code>ggplot</code>.</p>
  
  <pre><code>date &lt;- c("2016-03", "2016-04", "2016-05", "2016-06", "2016-07", "2016-08", 
  "2016-09", "2016-10", "2016-11", "2016-12")
  </code></pre>
  
  <p>I was using <code>parsedate::parse_date</code>, but since updating R it no longer functioning.</p>
  
  <p>I have looked at</p>
  
  <p><a href="https://stackoverflow.com/questions/21916503/format-date-year-month-in-r">Format Date (Year-Month) in R</a></p>
  
  <p><code>as.yearmon</code> works fine but it doesn't format to POSIXct which I need for <code>ggplot</code>. Other formatting such as <code>as.POSIXct</code> and <code>strptime</code> are giving NAs or errors.</p>
  
  <p>Note: I don't mind if the first of the month gets added to the "year-mo" format.</p>