fix: requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-14157807
- https://snyk.io/vuln/SNYK-PYTHON-DJANGO-14157810
- https://snyk.io/vuln/SNYK-PYTHON-SQLPARSE-14157217
- https://snyk.io/vuln/SNYK-PYTHON-URLLIB3-14192442
- https://snyk.io/vuln/SNYK-PYTHON-URLLIB3-14192443

Author: snyk-bot

requirements.txt

@@ -12,7 +12,7 @@ botocore>=1.35,<1.36
 celery>=5.2.6
 coverage>=4.5.4,<5.0    # Coverage 5.x moves from a json database to SQLite.  Moving to 5.x will require substantial rewrites in ietf.utils.test_runner and ietf.release.views
 defusedxml>=0.7.1    # for TastyPie when using xml; not a declared dependency
-Django>4.2,<5
+Django>4.2.27
 django-analytical>=3.1.0
 django-bootstrap5>=21.3
 django-celery-beat>=2.3.0
@@ -79,7 +79,8 @@ tblib>=1.7.0    # So that the django test runner provides tracebacks
 tlds>=2022042700    # Used to teach bleach about which TLDs currently exist
 tqdm>=4.64.0
 Unidecode>=1.3.4
-urllib3>=1.26,<2
+urllib3>=2.6.0
 weasyprint>=64.1
 xml2rfc>=3.23.0
 xym>=0.6,<1.0
+sqlparse>=0.5.4 # not directly required, pinned by Snyk to avoid a vulnerability