Half-orm

* [Fix] Regression in 0.6.2: dotted schema names were not handled properly. (0830a0c)

* [Fkeys] Fix insert, update and delete with constraints defined through foreign keys. (7bf9c77)
* [META] Change keys and fqrn to "<db>":"<schema>"."<relation>" (eada1b3)
* [CI] Build stage (4d836f2)
* [CI] Test from python 3.6 to 3.10 (ff3db37)

* [Transaction] Fix 6. Autocommit mode stays at False on rollback. (643f500)

Breaking change

There is a bug in the previous versions of the Transaction class.
If you use the Transaction class, **please upgrade to this release**.

* [Breaking change] Relation.join. (fdb4be8)
* [WIP] join on reverse fkeys. (73c3233)

Breaking change

`Relation.join` now accepts either a string or a list of strings.


lagaffe.join((Post(), 'posts', ['id']))


now returns `[{'id': value1}, {'id': value2}, ...]` instead of `[value1, value2, ...]`. It must be replaced by:


lagaffe.join((Post(), 'posts', 'id'))

* [Transaction] Fix 6. Autocommit mode stays at False on rollback. (643f500)

Breaking change

There is a bug in the previous versions of the Transaction class.
If you use the Transaction class, **please upgrade to this release**.

* Fix singleton decorator (97dec7e)