Build: Move pip installs to Python venv

Required due to brew adopting PEP 668
https://github.com/orgs/Homebrew/discussions/3404

Currently only required on macOS, and attempting to change breaks build
on Linux and Windows, so only changing macOS for now.

.github/workflows/build_uncrustify.yml

@@ -21,6 +21,8 @@ jobs:
 
       - name: Install Dependencies
         run: |
+          python3 -m venv ~/pyenv
+          source ~/pyenv/bin/activate
           python3 -m pip install -r requirements.txt
 
       - name: CI Bootstrap
@@ -29,6 +31,7 @@ jobs:
 
       - name: Build Uncrustify
         run: |
+          source ~/pyenv/bin/activate
           cd uncstrap && python3 ./uncstrap.py -b
           echo "UNC_SHA=$(cat unc-sha.txt)" >> $GITHUB_ENV
 

.github/workflows/main.yml

@@ -35,10 +35,14 @@ jobs:
 
       - name: Install Dependencies
         run: |
+          python3 -m venv ~/pyenv
+          source ~/pyenv/bin/activate
           python3 -m pip install -r requirements.txt
 
       - name: Run prospector
-        run: python3 -m prospector . -P ./prospector/profile.yml > prospector_result.txt || exit 1
+        run: |
+          source ~/pyenv/bin/activate
+          python3 -m prospector . -P ./prospector/profile.yml > prospector_result.txt || exit 1
 
       - name: Upload prospector result to Artifacts
         uses: actions/upload-artifact@v3