feat: change the default lance file format version to 2.1

[westonpace]

[westonpace]

Still debugging some test failures but giving the CI a chance to run

[codecov-commenter]

Codecov Report

:x: Patch coverage is 81.81818% with 56 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...e-encoding/src/encodings/logical/primitive/blob.rs	74.33%	23 Missing and 6 partials :warning:
.../lance-encoding/src/encodings/physical/constant.rs	38.09%	11 Missing and 2 partials :warning:
rust/lance-encoding/src/compression.rs	44.44%	4 Missing and 1 partial :warning:
rust/lance-encoding/src/decoder.rs	78.94%	3 Missing and 1 partial :warning:
.../lance-encoding/src/encodings/logical/primitive.rs	95.34%	2 Missing :warning:
...ust/lance-encoding/src/encodings/physical/value.rs	80.00%	2 Missing :warning:
rust/lance-file/src/v2/reader.rs	88.88%	1 Missing :warning:

:loudspeaker: Thoughts on this report? Let us know!

[westonpace]

Converting to a draft until https://github.com/lancedb/lance/pull/4840 is resolved (this PR now builds on top of that)