guix: update time-machine to 5cb84f2013c5b1e48a7d0e617032266f1e6059e2

Package updates:
(base) glibc 2.35 -> 2.39
binutils 2.38 -> 2.41
diffutils 3.8 -> 3.10
gawk 5.2.1 -> 5.3.0
git-minimal 2.45.2 -> 2.46.0
grep 3.8 -> 3.11
gzip 1.12 -> 1.13
linux-headers 6.1.106 -> 6.1.119
make 4.3 -> 4.4.1
xz 5.2.8 -> 5.4.5

CMake 3.30 becomes available.
Clang/LLVM 19 becomes available.

contrib/guix/libexec/prelude.bash

@@ -71,7 +71,7 @@ fi
 time-machine() {
     # shellcheck disable=SC2086
     guix time-machine --url=https://codeberg.org/guix/guix.git \
-                      --commit=53396a22afc04536ddf75d8f82ad2eafa5082725 \
+                      --commit=5cb84f2013c5b1e48a7d0e617032266f1e6059e2 \
                       --cores="$JOBS" \
                       --keep-failed \
                       --fallback \