ci: add double quote/no backslash lint

.flake8

 [flake8]
 [flake8]
 min_python_version = 3.6.0
 min_python_version = 3.6.0
 max-line-length = 88
 max-line-length = 88
+inline-quotes = double
 extend-ignore =
 extend-ignore =
     # E501: Line too long (FIXME: long string constants)
     # E501: Line too long (FIXME: long string constants)
     E501,
     E501,

.pre-commit-config.yaml

@@ -35,6 +35,7 @@ repos:
           - flake8-comprehensions==3.7.0
           - flake8-comprehensions==3.7.0
           - flake8-no-pep420==1.2.0
           - flake8-no-pep420==1.2.0
           - flake8-typing-imports==1.11.0
           - flake8-typing-imports==1.11.0
+          - flake8-quotes==3.3.1
 
 
   - repo: https://github.com/pycqa/isort
   - repo: https://github.com/pycqa/isort
     rev: 5.10.1
     rev: 5.10.1