Rename workflow file to just ci.yml

It doesn't seem appropriate to use test.yml for it.
diff --git a/.github/workflows/test.yml b/.github/workflows/ci.yml
similarity index 99%
rename from .github/workflows/test.yml
rename to .github/workflows/ci.yml
index 7c945c7..c6e6519 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/ci.yml
@@ -1,4 +1,4 @@
-name: test SWIG via CI
+name: CI
 
 on:
   push: