[newlib-cygwin] Cygwin: CI: Upgrade checkout actions to avoid deprecation warning

[Jon Turney <jturney@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=25d65d6ec0532742d2d4121e4ddfda6295a4da78

commit 25d65d6ec0532742d2d4121e4ddfda6295a4da78
Author: Jon Turney <jon.turney@dronecode.org.uk>
Date:   Sat Jul 22 13:23:15 2023 +0100

    Cygwin: CI: Upgrade checkout actions to avoid deprecation warning
    
    Also: workaround a problem with actions/checkout's post-run step using
    Cygwin git but being incompatible with it. (This would be better solved
    by cygwin-install-action having a post-run step to unwind it's PATH
    changes, but that's not currently possible)
    
    Signed-off-by: Jon Turney <jon.turney@dronecode.org.uk>

Diff:
---
 .github/workflows/cygwin.yml | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/cygwin.yml b/.github/workflows/cygwin.yml
index 145b59eba..1034495e6 100644
--- a/.github/workflows/cygwin.yml
+++ b/.github/workflows/cygwin.yml
@@ -15,7 +15,7 @@ jobs:
     name: Fedora cross ${{ matrix.target }}
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
 
     # install build tools
     - run: dnf install -y autoconf automake make patch perl
@@ -61,7 +61,7 @@ jobs:
     # endings, but this could still be dangerous e.g if we need symlinks in the
     # repo)
     - run: git config --global core.autocrlf input
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
 
     # install cygwin and build tools
     - name: Install Cygwin
@@ -131,3 +131,7 @@ jobs:
           build/${{ matrix.target }}/winsup/testsuite/**/*.log
           build/${{ matrix.target }}/winsup/testsuite/**/*.trs
       if: ${{ !cancelled() }}
+
+    # workaround problems with actions/checkout post-run step using cygwin git
+    - name: Avoid actions/checkout post-run step using Cygwin git
+      run: bash -c 'rm /usr/bin/git.exe'