phabricator: include the suggested arc config in the repo
Test Plan:
I uploaded this revision with `arc diff`
Differential Revision: https://phab.mercurial-scm.org/D171
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/.arcconfig Fri Jul 21 14:22:08 2017 +0000
@@ -0,0 +1,6 @@
+{
+ "conduit_uri": "https://phab.mercurial-scm.org/api",
+ "repository.callsign": "HG",
+ "arc.land.onto.default": "@",
+ "base": "hg:.^"
+}
--- a/tests/test-check-code.t Wed Jul 19 14:50:50 2017 -0700
+++ b/tests/test-check-code.t Fri Jul 21 14:22:08 2017 +0000
@@ -36,6 +36,7 @@
Prevent adding new files in the root directory accidentally.
$ testrepohg files 'glob:*'
+ .arcconfig
.editorconfig
.hgignore
.hgsigs