[ci] Move into a flat structure to facilitate testing

pyproject.toml

@@ -61,6 +61,11 @@ error-config = "exposed.tests.data.doesnt_exist"
 
 [tool.setuptools]
 zip-safe = false
+packages = [
+    "exposed",
+    "exposed.tests",
+    "exposed.tests.data",
+    ]
 
 [tool.setuptools.dynamic]
 version = {file = "version.txt"}
@@ -87,5 +92,4 @@ addopts = [
     "--cov-report=html:html/coverage",
     "--cov-report=xml:coverage.xml",
     "--junitxml=junit-coverage.xml",
-    "--pyargs", "exposed",
 ]