internal/rosa: key-value type

This type is used very frequently. The new type is much easier to type and can receive helper methods eventually if needed.

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

internal/rosa/zstd.go

@@ -14,7 +14,7 @@ func (t Toolchain) newZstd() (pkg.Artifact, string) {
 		pkg.TarGzip,
 	), nil, &CMakeHelper{
 		Append: []string{"build", "cmake"},
-		Cache: [][2]string{
+		Cache: []KV{
 			{"CMAKE_BUILD_TYPE", "Release"},
 		},
 	}), version