Fix Cygwin's ability to clone the repo

Author: ISSOtm

.github/workflows/testing.yml

@@ -323,27 +323,34 @@ jobs:
       fail-fast: false
     runs-on: windows-2022
     timeout-minutes: 30
+    defaults:
+      run:
+        shell: C:\cygwin\bin\env.exe CYGWIN_NOWINPATH=1 CHERE_INVOKING=1 C:\cygwin\bin\bash.exe -o igncr '{0}'
     steps:
       - name: Setup Cygwin
         uses: cygwin/cygwin-install-action@v6
         with:
           platform: ${{ matrix.arch }}
           packages: >-
+            ca-certificates
             bison
             gcc-g++
             git
             libpng-devel
             make
             pkg-config
+      - name: Reset directory ownership
+        working-directory: ..
+        run: |
+          rmdir rgbds
+          mkdir rgbds
       - name: Checkout repo
         uses: actions/checkout@v6
       - name: Build & install using Make
-        shell: C:\cygwin\bin\env.exe CYGWIN_NOWINPATH=1 CHERE_INVOKING=1 C:\cygwin\bin\bash.exe -o igncr '{0}'
         run: | # Cygwin does not support `make develop` sanitizers ASan or UBSan
           make -kj Q=
           make install -j Q=
       - name: Run tests
-        shell: C:\cygwin\bin\env.exe CYGWIN_NOWINPATH=1 CHERE_INVOKING=1 C:\cygwin\bin\bash.exe -o igncr '{0}'
         run: |
           test/run-tests.sh --only-internal