ci: Install meson (now required by picolibc).

.github/workflows/ci.yml

@@ -15,6 +15,8 @@ jobs:
         run: |
           sudo apt-get install wget build-essential python3
           pip3 install setuptools
+          pip3 install requests
+          pip3 install meson
 
       # Install (n)Migen / LiteX / Cores
       - name: Install LiteX