internal/rosa: helpers for common url formats

This cleans up call site of NewPackage.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/openssl.go

@@ -7,10 +7,11 @@ func (t Toolchain) newOpenSSL() (pkg.Artifact, string) {
 		version  = "3.6.2"
 		checksum = "jH004dXTiE01Hp0kyShkWXwrSHEksZi4i_3v47D9H9Uz9LQ1aMwF7mrl2Tb4t_XA"
 	)
-	return t.NewPackage("openssl", version, pkg.NewHTTPGetTar(
-		nil, "https://github.com/openssl/openssl/releases/download/"+
-			"openssl-"+version+"/openssl-"+version+".tar.gz",
-		mustDecode(checksum),
+	return t.NewPackage("openssl", version, newFromGitHubRelease(
+		"openssl/openssl",
+		"openssl-"+version,
+		"openssl-"+version+".tar.gz",
+		checksum,
 		pkg.TarGzip,
 	), &PackageAttr{
 		Env: []string{