pyproject: move all tox environment dependencies

This requires pip 21.2 for recursive optional dependencies:
https://hynek.me/articles/python-recursive-optional-dependencies/

While at it, also create a "dev" extra to install everything required
for a development environment, like so:
    python3 -m venv ircstream-venv
    . ircstream-venv/bin/activate
    pip install -U pip  # needed for PEP 660 support
    pip install -e .[dev]

Author: paravoid

pyproject.toml

@@ -38,6 +38,31 @@ dependencies = [
     "prometheus_client>=0.9.0",
     "structlog>=20.1.0",
 ]
+optional-dependencies.tests = [
+    "coverage[toml]",
+    "pytest",
+    "pytest-cov",
+    "pytest-asyncio",
+    "irc",
+    "pyyaml",
+]
+optional-dependencies.type = [
+    "ircstream[tests]",
+    "mypy",
+    "types-PyYAML",
+]
+optional-dependencies.lint = [
+    "ircstream[tests]",
+    "validate-pyproject[all]",
+    "ruff",
+    "black",
+    "pylint",
+]
+optional-dependencies.dev = [
+    "ircstream[tests]",
+    "ircstream[type]",
+    "ircstream[lint]",
+]
 
 [project.urls]
 homepage = "https://github.com/paravoid/ircstream"

tox.ini

@@ -11,27 +11,19 @@ source = ircstream.py tests/
 [testenv]
 usedevelop = True
 setenv = COVERAGE_FILE={toxworkdir}/.coverage.{envname}
-deps =
-    coverage[toml]
-    pytest
-    pytest-cov
-    pytest-asyncio
-    irc
-    pyyaml
+extras = tests
 commands = pytest --quiet --cov=ircstream
 parallel_show_output = True
 
 [testenv:py39-bullseye]
 deps =
     prometheus_client==0.9.0
     structlog==20.1.0
-    {[testenv]deps}
 
 [testenv:py311-bookworm]
 deps =
     prometheus_client==0.16.0
     structlog==22.3.0
-    {[testenv]deps}
 
 [testenv:coverage]
 skip_install = True
@@ -48,25 +40,17 @@ parallel_show_output = True
 
 [testenv:type]
 basepython = python3
-deps =
-    {[testenv]deps}
-    mypy
-    types-PyYAML
+extras = type
 commands =
     mypy {[main]source}
 parallel_show_output = True
 
 [testenv:lint]
 basepython = python3
+extras = lint
 commands =
     validate-pyproject pyproject.toml
     ruff {[main]source}
     pylint {[main]source}
     black --check {[main]source}
-deps =
-    {[testenv]deps}
-    validate-pyproject[all]
-    ruff
-    black
-    pylint
 parallel_show_output = True