guess release notes: special-case curl

[dscho]

Just as #35 did for OpenSSL, it would be nice if we could link directly to cURL's changelog from our Release Notes instead of the tag (git-for-windows/build-extra@120bab8 links to https://github.com/curl/curl/releases/tag/curl-8_2_0 but https://curl.se/changes.html#8_2_0 is probably a better link for anybody interested in the details).

[rimrul]

We do already special case curl (#34). And that works, if we add the release note from the issue (8.1.2, 8.2.1, 8.7.1) or the MSYS2-packages PR (8.6.0), but not from the MINGW-packages PR (8.4.0, 8.8.0),