Remove duplicate installs from GitHub build workflow

Author: sfe-SparkFro

.github/workflows/build.yml

@@ -19,7 +19,6 @@ jobs:
         submodules: true
     - name: Install packages
       run: |
-        sudo apt-get install gcc-arm-none-eabi libnewlib-arm-none-eabi
         sudo apt install cmake python3 build-essential gcc-arm-none-eabi libnewlib-arm-none-eabi libstdc++-arm-none-eabi-newlib
     - name: Build MPY Cross
       run: make -C micropython/mpy-cross