Add changesets for pre-monorepo changes (#536)
* Add changeset for urql-exchange-graphcache/pull/156
* Add changeset for urql-exchange-graphcache/pull/160
* Add changeset for urql-exchange-graphcache/pull/161
* Add changeset for urql/pull/512
* Add changeset for urql/pull/515
* Add changeset urql/pull/514
* Add changeset for urql/pull/518
* Add changeset for urql/pull/519
* Add changeset for urql/pull/512
* Fix manual "see links" for dependency release lines in Changelog gen
* Add changeset for @urql/preact
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