Add bare-bones Bazel CI configuration (#54)

diff --git a/.ci/subpar.json b/.ci/subpar.json
new file mode 100644
index 0000000..dc67a9c
--- /dev/null
+++ b/.ci/subpar.json
@@ -0,0 +1,3 @@
+[
+    {"node": "linux-x86_64"}
+]