Improve release notes for RC_v3.0.0

[lopierra]

Improve auto-generated release notes by highlighting major changes and filtering the granular changes.

https://github.com/include-dcc/include-linkml/releases/tag/v3.0.0_rc1

[lopierra]

#118 - ignore
#122 - ignore
#154: Update Assay component to include latest Virtual Biorepository model
#163 and #181: Update Study component and add new Dataset component to reflect new Study/Dataset pages

[lopierra]

#187 Added a new Dataset Manifest component to index files associated with Datasets; refactored LinkML to reuse slots

[monicacecilia]

done and done!