innosetup version script: use GitHub Releases URL

Inno Setup downloads have moved from jrsoftware.org to GitHub
Releases. The old URL at https://jrsoftware.org/download.php/
now returns 404 for current versions (e.g. 6.7.3), causing the
`/open pr` workflow to fail. The new URL is on GitHub at
https://github.com/jrsoftware/issrc/releases/ and encodes the
version with underscores in the tag name (e.g. `is-6_7_3`) while
keeping dots in the filename (e.g. `innosetup-6.7.3.exe`).

Assisted-by: Opus 4.6
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

update-scripts/version/innosetup

@@ -1,7 +1,8 @@
 #!/bin/sh
 
 set -x &&
-url="https://jrsoftware.org/download.php/innosetup-$1.exe" &&
+version_underscores="$(echo "$1" | tr . _)" &&
+url="https://github.com/jrsoftware/issrc/releases/download/is-$version_underscores/innosetup-$1.exe" &&
 curl -# -LR -D curl.log -o is.exe "$url" &&
 cat curl.log &&
 grep 'HTTP/.* 200' curl.log &&