internal/rosa: wrapper around git helper

This results in much cleaner call site for the majority of use cases.

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

internal/rosa/p11.go

@@ -7,9 +7,9 @@ func (t Toolchain) newP11Kit() (pkg.Artifact, string) {
 		version  = "0.26.2"
 		checksum = "3ei-6DUVtYzrRVe-SubtNgRlweXd6H2qHmUu-_5qVyIn6gSTvZbGS2u79Y8IFb2N"
 	)
-	return t.NewPackage("p11-kit", version, t.NewViaGit(
+	return t.NewPackage("p11-kit", version, t.newTagRemote(
 		"https://github.com/p11-glue/p11-kit.git",
-		"refs/tags/"+version, mustDecode(checksum),
+		version, checksum,
 	), nil, &MesonHelper{
 		Setup: []KV{
 			{"Dsystemd", "disabled"},