build: Add warning flags and set default env

platformio.ini

@@ -3,12 +3,21 @@
 ; This file is setup with a lot of suggestions for libraries etc.
 ;
 ; You can delete them as you wish :)
+;
+[platformio]
+description = My cool project
+
+; This is the default environment that will be used when you run `pio run`
+default_envs = raspberrypi-pico
+
 [env]
 framework = arduino
 
 ; Use C++ version 17
 build_unflags = -std=gnu++11
-build_flags = -std=gnu++17 -fconcepts
+
+; Support C++ 17 and enable some warnings
+build_flags = -std=gnu++17 -Wno-unused-variable -Wno-unused-but-set-variable -Wno-unused-function -Wno-format-extra-args -Wsign-compare -Wuninitialized -Wunused-parameter -Wunused
 
 ; Use clang-tidy when runnning `pio check`
 ; https://docs.platformio.org/en/stable/advanced/static-code-analysis/tools/clang-tidy.html