Fix build-debian-package.sh docs and document how to make an aarch64 deb

doc/release-process.md

@@ -122,3 +122,5 @@ Install deps on Linux:
 ## Platform-specific notes
 
 Use `./util/build-mac.sh` to compile on Apple/Mac systems, use `./util/build-win.sh` to build on Windows and `./util/build-arm.sh` to build on ARMv8 systems.
+
+Use `./util/build-debian-package.sh aarch64` to build a Debian package for aarch64 .

util/build-debian-package.sh

@@ -4,7 +4,7 @@
 # file COPYING or https://www.gnu.org/licenses/gpl-3.0.en.html
 ## Usages:
 ##  ./util/build-debian-package.sh               # build amd64 package
-##  ARCH=aarch64 ./util/build-debian-package.sh  # build package for specific archiecture
+##  ./util/build-debian-package.sh aarch64       # build package for specific archiecture
 
 ARCH=${1:-amd64}
 echo "Let There Be Hush Debian Packages"