[gnumeric] xlsx: Constify a table.

[Morten Welinder <mortenw src gnome org>]

commit f97df5c001b469a358ed2dda7d4cb86c91ae4135
Author: Morten Welinder <terra gnome org>
Date:   Mon Jan 31 12:47:19 2022 -0500

    xlsx: Constify a table.

 plugins/excel/xlsx-read.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/plugins/excel/xlsx-read.c b/plugins/excel/xlsx-read.c
index 866e8f060..78952bd1b 100644
--- a/plugins/excel/xlsx-read.c
+++ b/plugins/excel/xlsx-read.c
@@ -892,9 +892,9 @@ simple_string (G_GNUC_UNUSED GsfXMLIn *xin, xmlChar const **attrs)
  * TODO : Can we merge the code ?
  *       Will the 'indexedColors' look like a palette ?
  */
-static struct {
+static const struct {
        guint8 r, g, b;
-} xlsx_default_palette_v8 [] = {
+} xlsx_default_palette_v8[] = {
        {  0,  0,  0}, {255,255,255}, {255,  0,  0}, {  0,255,  0},
        {  0,  0,255}, {255,255,  0}, {255,  0,255}, {  0,255,255},