ci(snowflake): pin cryptography (#4857)

## Description

The 39 release of cryptography causes the snowflake test suite to fail
with Python < 3.7. Therefore we pin it to allow the CI jobs to pass for
now.

## Checklist
- [x] Followed the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/contributing.html#Release-Note-Guidelines)
when writing a release note.
- [x] Add additional sections for `feat` and `fix` pull requests.
- [x] [Library
documentation](https://github.com/DataDog/dd-trace-py/tree/1.x/docs)
and/or [Datadog's documentation
site](https://github.com/DataDog/documentation/) is updated. Link to doc
PR in description.

## Reviewer Checklist
- [x] Title is accurate.
- [x] Description motivates each change.
- [x] No unnecessary changes were introduced in this PR.
- [x] Avoid breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes unless absolutely necessary.
- [x] Tests provided or description of manual testing performed is
included in the code or PR.
- [x] Release note has been added and follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/contributing.html#Release-Note-Guidelines),
or else `changelog/no-changelog` label added.
- [x] All relevant GitHub issues are correctly linked.
- [x] Backports are identified and tagged with Mergifyio.

Author: P403n1x87

riotfile.py

@@ -1694,6 +1694,7 @@ def select_pys(min_version=MIN_PYTHON_VERSION, max_version=MAX_PYTHON_VERSION):
                             "~=2.0.0",
                             "~=2.1.0",
                         ],
+                        "cryptography": "<39",
                     },
                 ),
                 Venv(
@@ -1703,6 +1704,7 @@ def select_pys(min_version=MIN_PYTHON_VERSION, max_version=MAX_PYTHON_VERSION):
                         "snowflake-connector-python": [
                             "~=2.2.0",
                         ],
+                        "cryptography": "<39",
                     },
                 ),
                 Venv(
@@ -1712,6 +1714,7 @@ def select_pys(min_version=MIN_PYTHON_VERSION, max_version=MAX_PYTHON_VERSION):
                         "snowflake-connector-python": [
                             "~=2.3.0",
                         ],
+                        "cryptography": "<39",
                     },
                 ),
                 Venv(
@@ -1723,6 +1726,7 @@ def select_pys(min_version=MIN_PYTHON_VERSION, max_version=MAX_PYTHON_VERSION):
                             "~=2.6.0",
                             latest,
                         ],
+                        "cryptography": "<39",
                     },
                 ),
             ],