Add empty test to get release flow to pass (#5)

tests/BUILD.bazel

diff --git a/tests/BUILD.bazel b/tests/BUILD.bazel
new file mode 100644
index 0000000..faa7068
--- /dev/null
+++ b/tests/BUILD.bazel
@@ -0,0 +1,7 @@
+load("//shell:sh_test.bzl", "sh_test")
+
+# Placeholder test to get the release action's `bazel test` to pass.
+sh_test(
+    name = "test",
+    srcs = ["test.sh"],
+)

tests/test.sh

diff --git a/tests/test.sh b/tests/test.sh
new file mode 100755
index 0000000..f1f641a
--- /dev/null
+++ b/tests/test.sh
@@ -0,0 +1 @@
+#!/usr/bin/env bash