bump version to 8.1.0 and update release-notes.md

bump version to 8.0.0 and update release-notes.md

bump version to 7.8.1 and update release-notes.md

bump version to 7.8.0 and update release-notes.md

bump version to 7.7.0 and update release-notes.md

bump version to 7.6.0 and update release-notes.md

bump version to 7.5.0 and update release-notes.md

bump version to 7.4.0 and update release-notes.md

bump version to 7.3.0+for36 and update release-notes.md

bump version to 7.2.0 and update release-notes.md