*: migrate to CC toolchains and Bazel 5.4.0

Change-Id: Iff3c0ddda4413dd0c5fa657a5b7813223e98611e
Reviewed-on: https://review.monogon.dev/c/monogon/+/1079
Tested-by: Jenkins CI
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
diff --git a/.bazelversion b/.bazelversion
index af8c8ec..8a30e8f 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-4.2.2
+5.4.0