Teach MANIFEST and tox about ci->.ci

MANIFEST.in

@@ -46,7 +46,7 @@ recursive-include changelog.d *
 
 prune .circleci
 prune .github
-prune ci
+prune .ci
 prune contrib
 prune debian
 prune demo/etc

tox.ini

@@ -49,7 +49,7 @@ lint_targets =
     contrib
     synctl
     synmark
-    ci
+    .ci
     docker
 
 # default settings for all tox environments