use CRAN release version of janitor

- closes #32

A dependency on the dev/non-CRAN version (>= 2.0.1.9000) of {janitor} was added in #22, though it's not exactly clear why that was necessary. Since then, there have been multiple official CRAN releases and it's currently at v2.2.0. The first CRAN release following 2.0.1.9000 appears to have been 2.1.0

DESCRIPTION

@@ -24,7 +24,7 @@ Imports:
     ellipsis,
     fs,
     glue,
-    janitor (>= 2.0.1.9000),
+    janitor (>= 2.1.0),
     lifecycle,
     magrittr,
     purrr,
@@ -38,8 +38,6 @@ Suggests:
     rmarkdown,
     testthat (>= 2.1.0),
     withr
-Remotes: 
-    sfirke/janitor
 Encoding: UTF-8
 LazyData: true
 Roxygen: list(markdown = TRUE)