revert 91eafea: xfun 0.51 is on CRAN now

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: knitr
 Type: Package
 Title: A General-Purpose Package for Dynamic Report Generation in R
-Version: 1.49.7
+Version: 1.49.8
 Authors@R: c(
     person("Yihui", "Xie", role = c("aut", "cre"), email = "[email protected]", comment = c(ORCID = "0000-0003-0645-5666", URL = "https://yihui.org")),
     person("Abhraneel", "Sarma", role = "ctb"),
@@ -120,7 +120,7 @@ Imports:
     highr (>= 0.11),
     methods,
     tools,
-    xfun (>= 0.50),
+    xfun (>= 0.51),
     yaml (>= 2.1.19)
 Suggests:
     bslib,
@@ -199,3 +199,4 @@ Collate:
     'utils-vignettes.R'
     'zzz.R'
 RoxygenNote: 7.3.2
+Remotes: rstudio/tinytex

R/utils-upload.R

@@ -7,7 +7,5 @@
 #' @export
 #' @keywords internal
 imgur_upload = function(file, key = xfun::env_option('knitr.imgur.key'), ...) {
-  # TODO: remove this after xfun 0.51
-  if (is.null(key)) key = paste(rev(strsplit('01a236c49e09142','')[[1]]), collapse = '')
   xfun::upload_imgur(file, key, ..., include_xml = TRUE)
 }