V0.18.0 release notes (#1656)

* version bump

* group entries

* update the descriptions

* torch example

* contributors

* Update .github/CHANGELOG.md

Co-authored-by: Josh Izaac <[email protected]>

* Update .github/CHANGELOG.md

Co-authored-by: Josh Izaac <[email protected]>

* Update .github/CHANGELOG.md

* Update .github/CHANGELOG.md

Co-authored-by: Josh Izaac <[email protected]>

* Update .github/CHANGELOG.md

Co-authored-by: Josh Izaac <[email protected]>

* Update .github/CHANGELOG.md

Co-authored-by: Josh Izaac <[email protected]>

* Update .github/CHANGELOG.md

Co-authored-by: Josh Izaac <[email protected]>

* Update .github/CHANGELOG.md

Co-authored-by: Josh Izaac <[email protected]>

* Update .github/CHANGELOG.md

Co-authored-by: Josh Izaac <[email protected]>

* format lines

* num

* Update .github/CHANGELOG.md

Co-authored-by: Josh Izaac <[email protected]>

* move q transforms

* trainable coeffs

* SISWAP adjust

* Add link to changelog

* Fix merge

* SISWAP move to improvements

* drawer example

* remove item on separate requirements file

* Update .github/CHANGELOG.md

Co-authored-by: Josh Izaac <[email protected]>

* QFT move

* further suggestions

* NumPy

* draw example

* no grad call for finite_diff qml.gradients

* no grad call for param_shift

* lightning

* Update .github/CHANGELOG.md

Co-authored-by: Josh Izaac <[email protected]>

* Hamiltonian + its plot

* Hamiltonian param shift move

* bug fix phrasing

* contributors list

* Lightning adjoint plot & description

* Hamiltonian plot width

* align mid

* Revert "align mid"

This reverts commit 9b8d354.

Co-authored-by: Josh Izaac <[email protected]>
Co-authored-by: Tom Bromley <[email protected]>