fix: python/spec/fixtures/requirements/pip_compile_imports_shared.txt…

… to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-CRYPTOGRAPHY-6261585

python/spec/fixtures/requirements/pip_compile_imports_shared.txt

@@ -13,7 +13,7 @@ certifi==2018.10.15       # via requests
 cffi==1.11.5              # via cryptography
 chardet==3.0.4            # via requests
 cookies==2.2.1            # via moto
-cryptography==41.0.0       # via moto
+cryptography==42.0.4       # via moto
 docker-pycreds==0.3.0     # via docker
 docker==3.5.1             # via moto
 docutils==0.14            # via botocore