HEADS UP: New default for `ties.method` of {col,row}Ranks()

# Background

**matrixStats** uses `ties.method = "max"` as the default for `colRanks()` and `rowRanks()` for legacy reasons, but we want eventually update to `ties.method = "average"` to align it with `base::rank()`, cf. https://github.com/HenrikBengtsson/matrixStats/issues/142.

The process for this migration with be:

1. Give a deprecation warning if `ties.method` is not explicitly specified (long time; several releases)
2. Give a defunct error if `ties.method` is not explicitly specified (long time; several releases)
3. Switch the new default to `ties.method = "average"`

This will have to take a long time in order to make sure end-users out there will notice this and update their code. I hope this will minimize the risk for existing code all of a sudden start producing different results.

# Issue

**sparseMatrixStats** gives an ERROR when I revdep check asserting `!isTRUE(missing(ties.method))`, cf. https://github.com/HenrikBengtsson/matrixStats/blob/feature/default-rank-ties.method/revdep/R_MATRIXSTATS_TIES_METHOD_MISSING%3Ddefunct/problems.md#sparsematrixstats

まず sparseMatrixStats の colRanks() と rowRanks() の実装を調査し、リンク先の R_MATRIXSTATS_TIES_METHOD_MISSING=defunct レポートに記載された revdep の失敗を再現します。matrixStats の ties.method 移行によって sparseMatrixStats で missing(ties.method) エラーが発生しなくなれば、作業は完了です。

索引モデルが issue の本文から書いたものです。