Switch to a src-layout style repository layout

It's been shown that this style of layout has multiple advantages, and
most tools now support it out-of-the-box. This allows us to simplify a
bit of our configuration.

- https://setuptools.pypa.io/en/latest/userguide/package_discovery.html#src-layout

.github/workflows/ci.yml

@@ -36,7 +36,7 @@ jobs:
           isort --check --diff .
       - name: Typing
         run: |
-          python -m mypy -p vesta -p tests
+          python -m mypy
       - name: Tests
         run: |
-          python -m pytest -v --cov-config=setup.cfg
+          python -m pytest -v

pyproject.toml

@@ -38,27 +38,18 @@ Changelog = "https://github.com/jparise/vesta/blob/main/CHANGELOG.md"
 [tool.setuptools.dynamic]
 version = {attr = "vesta.__version__"}
 
-[tool.setuptools.package-data]
-vesta = ["py.typed"]
-
 [tool.coverage.run]
 branch = true
-source = [
-    "vesta",
-    "tests",
-]
+source = ["src"]
 
 [tool.isort]
 profile = "black"
 force_single_line = true
 multi_line_output = 3
 
 [tool.mypy]
+packages = ["vesta", "tests"]
 python_version = 3.8
 
 [tool.pytest.ini_options]
 addopts = "--cov=vesta --cov-report=term-missing --doctest-modules"
-testpaths = [
-    "vesta",
-    "tests",
-]