chore: clean up dev-dependencies and python version restrictions

poetry.lock

@@ -739,7 +739,7 @@ testing = ["pytest (>=4.6)", "pytest-checkdocs (>=2.4)", "pytest-flake8", "pytes
 [metadata]
 [metadata]
 lock-version = "1.1"
 lock-version = "1.1"
 python-versions = "^3.6"
 python-versions = "^3.6"
-content-hash = "3b47c507b3a73d5cb7e92b8d32b641f2266c46f70fabb5b00e82c79467d394a6"
+content-hash = "9d2e32899df46f2c63018e9a3f5e95dbbeb1ec41291c31289cff40f6f2d935a4"
 
 
 [metadata.files]
 [metadata.files]
 atomicwrites = [
 atomicwrites = [

pyproject.toml

@@ -39,7 +39,7 @@ cachecontrol = { version = "^0.12.9", extras = ["filecache"] }
 cachy = "^0.3.0"
 cachy = "^0.3.0"
 cleo = "^1.0.0a4"
 cleo = "^1.0.0a4"
 crashtest = "^0.3.0"
 crashtest = "^0.3.0"
-dataclasses = { version = "^0.8", python = "~3.6" }
+dataclasses = { version = "^0.8", python = "<3.7" }
 entrypoints = "^0.3"
 entrypoints = "^0.3"
 html5lib = "^1.0"
 html5lib = "^1.0"
 importlib-metadata = { version = "^1.6.0", python = "<3.8" }
 importlib-metadata = { version = "^1.6.0", python = "<3.8" }
@@ -63,8 +63,8 @@ pytest-sugar = "^0.9"
 pre-commit = { version = "^2.6", python = "^3.6.1" }
 pre-commit = { version = "^2.6", python = "^3.6.1" }
 deepdiff = "^5.0"
 deepdiff = "^5.0"
 httpretty = "^1.0"
 httpretty = "^1.0"
-typing-extensions = {version = "^4.0.0", python = "<3.8"}
-zipp = { version = "^3.4", python = "<3.8"}
+typing-extensions = { version = "^4.0.0", python = "<3.8" }
+zipp = { version = "^3.4", python = "<3.8" }
 
 
 [tool.poetry.scripts]
 [tool.poetry.scripts]
 poetry = "poetry.console.application:main"
 poetry = "poetry.console.application:main"