refactor(ci): use uploadconfig.note_file

Signed-off-by: Henri Menke <henri@henrimenke.de>

.github/workflows/main.yml

@@ -130,6 +130,15 @@ jobs:
         asset_name: pgf_${{ env.tagname }}.ctan.flatdir.zip.sig
         asset_content_type: text/plain
 
+    - name: "CTAN: Prepare fields"
+      run: |
+        cat <<'EOF' | tee CTAN_NOTES.md
+        The release files are signed using a detached signature.  You can obtain the
+        signature from the GitHub release page
+
+            https://github.com/pgf-tikz/pgf/releases/download/${{ env.tagname }}/pgf_${{ env.tagname }}.ctan.flatdir.zip.sig
+        EOF
+
     - name: "CTAN: Validate"
       run: |
         l3build upload --dry-run "$tagname"

build.lua

@@ -61,11 +61,7 @@ uploadconfig = {
   description = [[<p>PGF is a macro package for creating graphics. It is platform- and format-independent and works together with the most important TeX backend drivers, including pdfTeX and dvips. It comes with a user-friendly syntax layer called TikZ.<br></p><p>Its usage is similar to <a data-cke-saved-href="/pkg/pstricks-base" href="/pkg/pstricks-base">pstricks</a> and the standard picture environment. PGF works with plain (pdf-)TeX, (pdf-)LaTeX, and ConTeXt. Unlike <a data-cke-saved-href="/pkg/pstricks-base" href="/pkg/pstricks-base">pstricks</a>, it can produce either PostScript or PDF output.<br></p>]],
   email = "pgf-tikz@tug.org",
   license = "fdl;gpl2;lppl1.3c",
-  note = [[
-The release files are signed using a detached signature.  You can obtain the
-signature from the GitHub release page
-
-    https =//github.com/pgf-tikz/pgf/releases/download/${{ env.GIT_TAG }}/pgf_${{ env.GIT_TAG }}.ctan.flatdir.zip.sig]],
+  note_file = "CTAN_NOTES.md",
   pkg = "pgf",
   repository = "https://github.com/pgf-tikz/pgf",
   summary = "Create PostScript and PDF graphics in TeX",