fix(e2e): update flit_core to 3.10.1 for Python 3.14 compatibility

flit_core 3.9.0 uses ast.Str which was removed in Python 3.14,
causing test_override.sh to fail. Update to 3.10.1 which supports
all Python versions 3.11-3.14.

Co-Authored-By: Claude <claude@anthropic.com>

Signed-off-by: Ioannis Angelakopoulos <iangelak@redhat.com>

Author: iangelak

e2e/test_override.sh

@@ -23,7 +23,7 @@ fromager \
   --wheels-repo="$OUTDIR/wheels-repo" \
   --work-dir="$OUTDIR/work-dir" \
   --patches-dir "$SCRIPTDIR/flit_core_patches" \
-  bootstrap 'flit_core==3.9.0'
+  bootstrap 'flit_core==3.10.1'
 
 find "$OUTDIR/wheels-repo/simple/" -name '*.whl'
 
@@ -50,9 +50,9 @@ fi
 
 # Check for output files
 EXPECTED_FILES="
-wheels-repo/downloads/flit_core-3.9.0-0-py3-none-any.whl
+wheels-repo/downloads/flit_core-3.10.1-0-py3-none-any.whl
 
-sdists-repo/downloads/flit_core-3.9.0.tar.gz
+sdists-repo/downloads/flit_core-3.10.1.tar.gz
 "
 
 for f in $EXPECTED_FILES; do