debian: Update to debhelper-compat version 13

Signed-off-by: Keith Packard <keithp@keithp.com>

debian/control

@@ -4,7 +4,7 @@ Priority: optional
 Maintainer: Keith Packard <keithp@keithp.com>
 Homepage: https://keithp.com
 Rules-Requires-Root: no
-Build-Depends: debhelper-compat (= 12), libreadline-dev, avr-libc, gcc-avr,
+Build-Depends: debhelper-compat (= 13), libreadline-dev, avr-libc, gcc-avr,
  binutils-arm-none-eabi, gcc-arm-none-eabi, picolibc-arm-none-eabi (>= 1.4),
  binutils-riscv64-unknown-elf, gcc-riscv64-unknown-elf, picolibc-riscv64-unknown-elf (>= 1.4),
  python3, lola, gawk, asciidoctor, ruby-asciidoctor-pdf, ruby-coderay, qemu-system-arm,