Releasing Substrate 3.0/0.9 - Apollo 14

Latest release

Adding Changelog entry for patch release

Backport paritytech#7854

...to fix compilation error when using futures-* v0.3.9.

Fix offchain election to respect the weight (paritytech#7215)

* Mockup

* Fix offchain election to respect the weight

* Fix builds a bit

* Update frame/staking/src/offchain_election.rs

Co-authored-by: Shawn Tabrizi <[email protected]>

* Update frame/staking/src/offchain_election.rs

Co-authored-by: Shawn Tabrizi <[email protected]>

* Make it build, binary search

* Fix a number of grumbles

* one more fix.

* remove unwrap.

* better alg.

* Better alg again.

* Final fixes

* Fix

* Rollback to normal

* Final touches.

* Better tests.

* Update frame/staking/src/lib.rs

Co-authored-by: Guillaume Thiolliere <[email protected]>

* Proper maxExtWeight

* Final fix

* Final fix for the find_voter

Co-authored-by: Shawn Tabrizi <[email protected]>
Co-authored-by: Guillaume Thiolliere <[email protected]>

Tagging 2.0.0 for release

tagging for check to release

tagging 2.0

tagging 2.0

Tagging v2.0.0-rc6 - Rock Hyrax