chore: Upgrade Python requirements

requirements/edx-sandbox/base.txt

@@ -3,7 +3,7 @@
 # directly instead of using uv. Source of truth: requirements/edx-sandbox/pyproject.toml / uv.lock.
 # This file was autogenerated by uv via the following command:
 #    uv export --frozen --no-hashes --no-emit-project
-cffi==2.0.0 ; platform_python_implementation != 'PyPy'
+cffi==2.1.1 ; platform_python_implementation != 'PyPy'
     # via cryptography
 chem==2.0.0
     # via edx-sandbox
@@ -17,10 +17,12 @@ colorama==0.4.6 ; sys_platform == 'win32'
     #   tqdm
 contourpy==1.3.3
     # via matplotlib
-cryptography==49.0.0
+cryptography==50.0.0
     # via edx-sandbox
 cycler==0.12.1
     # via matplotlib
+defusedxml==0.7.1
+    # via nltk
 fonttools==4.63.0
     # via matplotlib
 joblib==1.5.3
@@ -38,13 +40,13 @@ markupsafe==3.0.3
     # via
     #   chem
     #   openedx-calc
-matplotlib==3.11.0
+matplotlib==3.11.1
     # via edx-sandbox
 mpmath==1.3.0
     # via sympy
 networkx==3.6.1
     # via edx-sandbox
-nltk==3.9.4
+nltk==3.10.3
     # via
     #   chem
     #   edx-sandbox
@@ -57,9 +59,9 @@ numpy==1.26.4
     #   scipy
 openedx-calc==5.0.0
     # via edx-sandbox
-packaging==26.2
+packaging==26.3
     # via matplotlib
-pillow==12.2.0
+pillow==12.3.0
     # via matplotlib
 pycparser==3.0 ; implementation_name != 'PyPy' and platform_python_implementation != 'PyPy'
     # via cffi
@@ -73,7 +75,7 @@ python-dateutil==2.9.0.post0
     # via matplotlib
 random2==1.0.2
     # via edx-sandbox
-regex==2026.6.28
+regex==2026.7.19
     # via nltk
 scipy==1.17.1
     # via
@@ -85,5 +87,5 @@ sympy==1.14.0
     # via
     #   edx-sandbox
     #   openedx-calc
-tqdm==4.68.3
+tqdm==4.70.0
     # via nltk