Re-add CMSIS MCU description file and a utility to manage it (#282)

* Start adding CMSIS MCU description tool

* Add 'add-missing'

* Switch MCU descriptions to JSON5

* Add new MCU after rebase

* Use virtualenv instead of APT for installing packages

* Also remove apt requirements files

* Wrong command!

* Check if index file exists before checking update time

* Respond to comments

* Make must_exist keyword only

---------

Co-authored-by: Victor Tang <[email protected]>

Author: Jamie Smith

.github/workflows/basic_checks.yml

@@ -164,16 +164,24 @@ jobs:
       -
         name: Checkout repo
         uses: actions/checkout@v3
+        
+      - name: Install python3-venv
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y python3-venv
 
       -
         name: install dependencies
         run: |
-          xargs sudo apt-get install -y < tools/requirements.apt.txt
-          xargs sudo apt-get install -y < tools/python/python_tests/requirements.apt.txt
+          python3 -m venv venv
+          source venv/bin/activate
+          pip install -r tools/requirements.txt
+          pip install -r tools/python/python_tests/requirements.txt
 
       -
         name: Python Tests
         run: |
+          source venv/bin/activate
           cd tools/python
           ./run_python_tests.sh