Fix missing 'packaging' requirement

The `sqlalchemy` instrumentation uses the `packaging` library to parse
the `sqlalchemy` SemVer.

`packaging` is not part of the standard library and should be included
in the `setup.cfg` file to avoid:

```
ModuleNotFoundError: No module named 'packaging'
```

Author: mattoberle

Diff for: CHANGELOG.md

@@ -8,6 +8,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased](https://github.com/open-telemetry/opentelemetry-python/compare/v1.5.0-0.24b0...HEAD)
 - `opentelemetry-sdk-extension-aws` Release AWS Python SDK Extension as 1.0.0
   ([#667](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/667))
+- `opentelemetry-instrumentation-sqlalchemy` Added `packaging` dependency
+  ([#713](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/713))
 
 ### Added
 - `opentelemetry-instrumentation-elasticsearch` Added `response_hook` and `request_hook` callbacks

Diff for: instrumentation/opentelemetry-instrumentation-sqlalchemy/setup.cfg

@@ -41,6 +41,7 @@ install_requires =
     opentelemetry-api ~= 1.3
     opentelemetry-semantic-conventions == 0.24b0
     opentelemetry-instrumentation == 0.24b0
+    packaging >= 21.0
     wrapt >= 1.11.2
 
 [options.extras_require]