Release notes for 3.0 (dotnet#6888)

* release notes 3.0

* Apply suggestions from code review

Co-authored-by: Jeff Handley <[email protected]>

* updates from pr

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Co-authored-by: Jeff Handley <[email protected]>

Adds the ability to load a pre-trained LightGBM file and import it in…

…to ML.Net. (dotnet#6569)

* need to finish multiclass

* multiclass

* reverting test for now

* reverting test for now

* added test and fixed objective parsing

* minor testing changes

Cherry picking PR that fixes official build. (dotnet#6468)

Merging since it has already been validated in the official build and is already in main.

Update versioning to 1.7.1 / 0.19.1 (dotnet#6122)

Update versioning to 1.7.1 / 0.19.1 (dotnet#6122)

Release notes for 1.7.0 preview (dotnet#5982)

updated official build yml to latest version (dotnet#5877)

Added in release notes for 1.5.5 (dotnet#5639)

* added in release notes

* Update release-1.5.5.md

Removed incorrect PR.

* Update docs/release-notes/1.5.5/release-1.5.5.md

Co-authored-by: Eric StJohn <[email protected]>

* Update docs/release-notes/1.5.5/release-1.5.5.md

Co-authored-by: Eric StJohn <[email protected]>

* Update release-1.5.5.md

Co-authored-by: Eric StJohn <[email protected]>

Fixed version numbers in the right place (dotnet#5558)

* Updated version to 1.5.4

* Updated version to 1.5.4

Created v1.5.2 relase notes (dotnet#5373)

* Created v1.5.2 relase notes

* Updated notes from review comments

* Updated release notes