Fix broken end-to-end tests by no longer using an editable package there, a work-around for https://github.com/pypa/packaging-problems/issues/609

tests/end-to-end/docker-compose.yaml

@@ -23,6 +23,7 @@ services:
       - "../..:/app:ro"
     tmpfs:
       - "/app/borgmatic.egg-info"
+      - "/app/build"
     tty: true
     working_dir: /app
     entrypoint: /app/scripts/run-full-tests

tox.ini

@@ -27,7 +27,9 @@ commands =
     pytest {posargs}
 
 [testenv:end-to-end]
+usedevelop = False
 deps = -rtest_requirements.txt
+       .
 passenv = COVERAGE_FILE
 commands =
     pytest {posargs} --no-cov tests/end-to-end