it seems I can't use ${{}} in code

Author: yihui

.github/workflows/R-CMD-check.yaml

@@ -33,6 +33,7 @@ jobs:
 
     env:
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
+      URL_DEPLOY_DOCS: ${{ secrets.URL_DEPLOY_DOCS }}
       R_KEEP_PKG_SOURCE: yes
       _R_CHECK_FORCE_SUGGESTS_: false
       _R_CHECK_RD_XREFS_: false
@@ -87,4 +88,4 @@ jobs:
           git config user.name "Yihui Xie"
           git config user.email "[email protected]"
           git add .
-          git commit -m "update docs" && git push && curl -X POST ${{secrets.URL_DEPLOY_DOCS}} || true
+          git commit -m "update docs" && git push && curl -X POST ${URL_DEPLOY_DOCS} || true

docs/01-start.Rmd

@@ -1,5 +1,9 @@
 # Get Started {#chp:start}
 
+> I can at least listen without indignation to the critic who is of the opinion that when one surveys the aims of cultural endeavour and the means it employs, one is bound to come to the conclusion that the whole effort is not worth the trouble, and that the outcome of it can only be a state of affairs which the individual will be unable to tolerate.
+> 
+> ---Sigmund Freud, _Civilization and Its Discontents_
+
 R Markdown documents need to be compiled to Markdown before being rendered to a
 target output format such as HTML and LaTeX.