appveyor.yml: update pip, hererocks, add Lua 5.4

appveyor.yml

@@ -1,32 +1,40 @@
 version: 0.0.1.{build}-test
 
-# Use default image unless needed
-#os:
-#- Windows Server 2012 R2
-
 shallow_clone: true
 
+matrix:
+  fast_finish: true
+
 environment:
   matrix:
-  - LUA: "lua 5.1"
-  - LUA: "lua 5.2 --compat none"
-  - LUA: "lua 5.3 --compat none"
-  - LUA: "luajit 2.1"
+  - LUAT: "lua"
+    LUAV: "5.1"
+  - LUAT: "lua"
+    LUAV: "5.2"
+    HEREROCKS_FLAGS: "--compat none"
+  - LUAT: "lua"
+    LUAV: "5.3"
+    HEREROCKS_FLAGS: "--compat none"
+  - LUAT: "lua"
+    LUAV: "5.4"
+    HEREROCKS_FLAGS: "--compat none"
+  - LUAT: "luajit"
+    LUAV: "2.1"
 
 # Abuse this section so we can have a matrix with different Compiler versions
 configuration:
   - mingw
   - vs_32
   - vs_64
 
-install:
-  - set PATH=%CD%\env\bin;C:\Python27\Scripts;C:\MinGW\bin;%PATH%
-  - pip install hererocks
-  - hererocks env --%LUA% --target %configuration% --luarocks latest
-
 before_build:
-# @todo
-- echo "Installing external deps"
+  - set PATH=C:\MinGW\bin;%PATH%
+  - set PATH=C:\Python37;C:\Python37\Scripts;%PATH% # Add directory containing 'pip' to PATH
+  - IF NOT EXIST lua_install-%LUAV%\bin\activate.bat ( pip install --upgrade certifi )
+  - FOR /F "tokens=* USEBACKQ" %%F IN (`python -c "import certifi;print(certifi.where())"`) DO ( SET SSL_CERT_FILE=%%F )
+  - IF NOT EXIST lua_install-%LUAV%\bin\activate.bat ( pip install hererocks )
+  - IF NOT EXIST lua_install-%LUAV%\bin\activate.bat ( hererocks lua_install-%LUAV% --%LUAT% %LUAV% %HEREROCKS_FLAGS% --luarocks latest --target=%configuration% )
+  - call lua_install-%LUAV%\bin\activate
 
 build_script:
 - luarocks make
@@ -37,5 +45,9 @@ test_script:
 - echo "Testing..."
 - lua tests/test.lua
 
-after_test:
-# @todo
+cache:
+  - lua_install-5.4
+  - lua_install-5.3
+  - lua_install-5.2
+  - lua_install-5.1
+  - lua_install-2.1