move combine back to post-build

The paths are even weirder inside the build environment.

.circleci/report-coverage.sh

 #! /usr/bin/env nix-shell
 #! nix-shell -i bash -p "python.withPackages (ps: [ ps.codecov ])"
+set -x
 find ./result-doc/share/doc
-cp ./result-doc/share/doc/*/.coverage ./
+cp ./result-doc/share/doc/*/.coverage.* ./
+python -m coverage combine
 python -m coverage report
 python -m coverage xml
 codecov --file coverage.xml

zkapauthorizer.nix

@@ -58,10 +58,8 @@ buildPythonPackage rec {
 
   postCheck = if collectCoverage
     then ''
-    python -m coverage combine
-    python -m coverage html
     mkdir -p "$doc/share/doc/${name}"
-    cp -vr .coverage htmlcov "$doc/share/doc/${name}"
+    cp -v .coverage.* "$doc/share/doc/${name}"
     ''
     else "";
 }