Move dev deps to extra (#206)

Author: mxr

requirements-dev.txt

@@ -32,6 +32,13 @@ python_requires = >=3.12
 console_scripts =
     sqlite-export-for-ynab = sqlite_export_for_ynab._main:main
 
+[options.extras_require]
+dev =
+    covdefaults>=2.1.0
+    coverage
+    pytest
+    pytest-asyncio
+
 [options.package_data]
 * = *.sql
 sqlite_export_for_ynab =
@@ -47,7 +54,7 @@ plugins = covdefaults
 envlist = py,pypy3,pre-commit
 
 [testenv]
-deps = -rrequirements-dev.txt
+extras = dev
 commands =
     coverage erase
     coverage run -m pytest {posargs:tests}