fix: requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-FONTTOOLS-6133203
- https://snyk.io/vuln/SNYK-PYTHON-NUMPY-2321964
- https://snyk.io/vuln/SNYK-PYTHON-NUMPY-2321966
- https://snyk.io/vuln/SNYK-PYTHON-NUMPY-2321970
- https://snyk.io/vuln/SNYK-PYTHON-PILLOW-5918878
- https://snyk.io/vuln/SNYK-PYTHON-PILLOW-6043904
- https://snyk.io/vuln/SNYK-PYTHON-PILLOW-6182918
- https://snyk.io/vuln/SNYK-PYTHON-PILLOW-6219984
- https://snyk.io/vuln/SNYK-PYTHON-PILLOW-6219986
- https://snyk.io/vuln/SNYK-PYTHON-PILLOW-6514866

requirements.txt

@@ -2,10 +2,12 @@
 click
 Cython
 matplotlib>=3.2.1
-numpy>=1.18.4
+numpy>=1.22.2
 opencv_contrib_python
 Shapely
 
 # Packaging
 setuptools>=40.6.3
-wheel>=0.32.3
+wheel>=0.32.3
+fonttools>=4.43.0 # not directly required, pinned by Snyk to avoid a vulnerability
+pillow>=10.3.0 # not directly required, pinned by Snyk to avoid a vulnerability