Automated update to Github CI to rustc nightly-2026-04-04

Update Nightly Rustc Bot · Update Nightly Rustc Bot · commit f1b2d3a9a0a6 · 2026-04-06T00:57:46.000Z
diff --git a/nightly-version b/nightly-version
@@ -1 +1 @@
-nightly-2025-09-27
+nightly-2026-04-04
