Removed automap deprecation warning

Fixed a deprecation warning that was emitted when using
:func:`_automap.automap_base` without passing an existing
``Base``.

Fixes: #6529

<!-- Provide a general summary of your proposed changes in the Title field above -->

### Description
Fixed the automap's declarative import from sqlalchemy.orm instead from the deprecated ext.declarative package

### Checklist
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This pull request is:

- [ ] A documentation / typographical error fix
	- Good to go, no issue or tests are needed
- [x] A short code fix
	- please include the issue number, and create an issue if none exists, which
	  must include a complete example of the issue.  one line code fixes without an
	  issue and demonstration will not be accepted.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.   one line code fixes without tests will not be accepted.
- [ ] A new feature implementation
	- please include the issue number, and create an issue if none exists, which must
	  include a complete example of how the feature would look.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.

**Have a nice day!**

Closes: #6533
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/6533
Pull-request-sha: 46d40005eae51fd7423da66f6ad4072f65744c1c

Change-Id: I432df70d4221873ca229076d5d3ac20b2870c13b

2 files changed, 9 insertions, 1 deletions

diff --git a/doc/build/changelog/unreleased_14/6529.rst b/doc/build/changelog/unreleased_14/6529.rst
new file mode 100644
index 000000000..df650cb43
--- /dev/null
+++ b/doc/build/changelog/unreleased_14/6529.rst
@@ -0,0 +1,8 @@
+.. change::
+    :tags: bug, ext
+    :tickets: 6529
+
+    Fixed a deprecation warning that was emitted when using
+    :func:`_automap.automap_base` without passing an existing
+    ``Base``.
+
diff --git a/lib/sqlalchemy/ext/automap.py b/lib/sqlalchemy/ext/automap.py
index 3d2e3eb29..e20435911 100644
--- a/lib/sqlalchemy/ext/automap.py
+++ b/lib/sqlalchemy/ext/automap.py
@@ -560,9 +560,9 @@ be applied as::
 
 
 """  # noqa
-from .declarative import declarative_base as _declarative_base
 from .. import util
 from ..orm import backref
+from ..orm import declarative_base as _declarative_base
 from ..orm import exc as orm_exc
 from ..orm import interfaces
 from ..orm import relationship