Elevate gitconfig to system level

for some reason, on GHA (only?), git unable to read ~/.gitconfig
so, whenever commit will get following error

```
git am
Committer identity unknown

*** Please tell me who you are.

Run

  git config --global user.email "you@example.com"
  git config --global user.name "Your Name"

to set your account's default identity.
Omit --global to set the identity only in this repository.

fatal: unable to auto-detect email address (got 'unknown@bcf9ba01cdb2.(none)')
```

This CL elevates gitconfig to system level to mitigate the issue.

Signed-off-by: nanake <nanake@users.noreply.github.com>

images/base-win32/Dockerfile

@@ -33,9 +33,9 @@ RUN <<EOF
         xxd \
         yasm
     dnf5 clean all
-    git config --global user.email "builder@localhost"
-    git config --global user.name "Builder"
-    git config --global advice.detachedHead false
+    git config --system user.email "builder@localhost"
+    git config --system user.name "Builder"
+    git config --system advice.detachedHead false
 EOF
 
 RUN --mount=src=.,dst=/input <<EOF

images/base-win64/Dockerfile

@@ -33,9 +33,9 @@ RUN <<EOF
         xxd \
         yasm
     dnf5 clean all
-    git config --global user.email "builder@localhost"
-    git config --global user.name "Builder"
-    git config --global advice.detachedHead false
+    git config --system user.email "builder@localhost"
+    git config --system user.name "Builder"
+    git config --system advice.detachedHead false
 EOF
 
 RUN --mount=src=.,dst=/input <<EOF