Add missing file for release automation (#592)

This tells Bazel where to put caches so that it lines up with GitHub Actions restoring them to the next worker

Author: alexeagle

.github/workflows/ci.bazelrc

@@ -0,0 +1,8 @@
+# Bazel settings to apply on CI only
+# Included with a --bazelrc option in the call to bazel
+build --announce_rc
+test --test_output=errors
+build --disk_cache=$HOME/.cache/bazel
+build --repository_cache=$HOME/.cache/bazel-repo
+# For bazel-in-bazel testing
+test --test_env=XDG_CACHE_HOME