Make source code font weight 600

Change-Id: Ibfbe97d05ca9c05379e344c42f4d73c54a096e71
diff --git a/inst/rmarkdown/templates/posterdown_ids/resources/template.html b/inst/rmarkdown/templates/posterdown_ids/resources/template.html
index 8fbd1af..dd55a19 100644
--- a/inst/rmarkdown/templates/posterdown_ids/resources/template.html
+++ b/inst/rmarkdown/templates/posterdown_ids/resources/template.html
@@ -350,6 +350,7 @@
 background-color: transparent;
 width: $if(codechunk_width)$$codechunk_width$$else$100%$endif$;
 font-size: $if(codechunk_textsize)$$codechunk_textsize$$else$20pt$endif$;
+font-weight: 600;
 margin-left: auto;
 margin-right: auto;
 }