Bump dev version v0.4.1.9000

DESCRIPTION

@@ -1,7 +1,7 @@
 Type: Package
 Package: xaringanthemer
 Title: Custom 'xaringan' CSS Themes
-Version: 0.4.1
+Version: 0.4.1.9000
 Authors@R: 
     person("Garrick", "Aden-Buie", , "garrick@adenbuie.com", role = c("aut", "cre"),
            comment = c(ORCID = "0000-0002-7111-0077"))