firmware: bump CMake requirement to 3.12.

.github/workflows/build.yml

@@ -160,10 +160,10 @@ jobs:
       matrix:
         os: ['macos', 'ubuntu', 'windows']
         board: ['HACKRF_ONE', 'JAWBREAKER', 'RAD1O', 'PRALINE', 'UNIVERSAL']
-        cmake: ['3.10.0', 'latest']
+        cmake: ['3.12.0', 'latest']
         exclude:
           - os: 'windows'
-            cmake: '3.10.0'
+            cmake: '3.12.0'
           # GitHub doesn't give us many macOS runners, so don't build for every board.
           # We just need to know that building firmware works on macOS. Use PRALINE
           # since that's the most complicated one due to FPGA bitstreams.

.github/workflows/includes-check.yml

@@ -14,7 +14,7 @@ jobs:
     strategy:
       matrix:
         board: ['HACKRF_ONE', 'JAWBREAKER', 'RAD1O', 'PRALINE', 'UNIVERSAL']
-        cmake: ['3.10.0', 'latest']
+        cmake: ['3.12.0', 'latest']
 
       # Don't cancel all builds when one fails
       fail-fast: false

firmware/CMakeLists.txt

@@ -23,7 +23,7 @@
 option(CHECK_INCLUDES
 	   "Check firmware sources for unused includes and transitive dependencies. (Requires iwyu)" OFF)
 
-cmake_minimum_required(VERSION 3.10.0)
+cmake_minimum_required(VERSION 3.12.0)
 set(CMAKE_TOOLCHAIN_FILE toolchain-arm-cortex-m.cmake)
 
 project (hackrf_firmware_all C)