chore: bump version to 2.26.0

Merge pull request #565 from cowprotocol/release/2.25

Release/2.25

chore: release - Merge pull request #542 from cowprotocol/release/2.24.0

Release/2.24.0

Merge pull request #523 from cowprotocol/release/2.23

Release/2.23.0

Merge pull request #506 from cowprotocol/release/2.22.0

Release: 2.22.0

chore: bump version

Merge pull request #476 from cowprotocol/release/2.21.0

Release/2.21.0

Merge pull request #446 from cowprotocol/release/2.20.0

2.20.0 Relese - partial fills

2.19.1 (#409)

Merge pull request #396 from cowprotocol/release/2.19.0

Release/2.19.0