ci: fix mingw checks by pinning (#3375)

* Workaround for https://github.com/msys2/setup-msys2/issues/167
* Adapted from https://github.com/cocotb/cocotb/commit/05036cb24d10579647e81dc1a405b126f711a66f

.github/workflows/ci.yml

@@ -892,7 +892,8 @@ jobs:
           - { sys: mingw64, env: x86_64 }
           - { sys: mingw64, env: x86_64 }
           - { sys: mingw32, env: i686 }
           - { sys: mingw32, env: i686 }
     steps:
     steps:
-    - uses: msys2/setup-msys2@v2
+    # Force version because of https://github.com/msys2/setup-msys2/issues/167
+    - uses: msys2/setup-msys2@v2.4.2
       with:
       with:
         msystem: ${{matrix.sys}}
         msystem: ${{matrix.sys}}
         install: >-
         install: >-