update scripts

Modernize CMake usage in scripts to define a build directory
using the cmake -B flag, use cmake --build rather than just make.

ci-scripts/install-firmware.sh

@@ -2,8 +2,7 @@
 set -e
 git submodule init
 git submodule update
-mkdir firmware/hackrf_usb/build
-cd firmware/hackrf_usb/build
-cmake ..
-make
-cd ../../..
+cd firmware/hackrf_usb
+cmake -B build
+cmake --build build
+cd ../..

ci-scripts/install-host.sh

@@ -1,7 +1,6 @@
 #!/bin/bash
 set -e
-mkdir host/build
-cd host/build
-cmake ..
-make
-cd ../..
+cd host
+cmake -B build
+cmake --build build
+cd ..