scripts/generate-release-changelog-links.hs: fixup dep and add note

Author: nfrisby

scripts/generate-release-changelog-links.hs

@@ -8,7 +8,7 @@
     case-insensitive,
     containers,
     foldl,
-    github,
+    github ^>= 0.28,
     optparse-applicative,
     pandoc ^>= 3.1,
     prettyprinter,
@@ -25,6 +25,9 @@
   ghc-options: -Wall -Wextra -Wcompat
 -}
 
+-- `nix build .#project.x86_64-linux.plan-nix.json` is a reliable way to
+-- generate the `plan.json` to be fed to this script.
+
 module Main (main) where
 
 import           Cabal.Plan