Merge branch 'maint'

.github/workflows/ci.yml

@@ -52,6 +52,7 @@ jobs:
           - uses: actions/checkout@v2
           - name: Install dependencies
             run: |
+                sudo apt update --fix-missing
                 sudo apt install -y libpython2-dev libpython3-dev python-numpy python3-numpy doxygen luajit lua-ldoc
 
                 # LuaRocks stopped installing properly through apt, so just copy the file from its repo